Led tube lamp

ABSTRACT

An LED tube lamp, comprising a lamp tube, which includes a light transmissive portion, a reinforcing portion and an end cap; an LED module, which includes an LED light source and an LED light strip; and a power supply module, which includes a set of N electronic components operably interconnected to drive the LED light source, wherein: the light transmissive portion is fixedly connected to the reinforcing portion; the reinforcing portion includes a platform and a bracing structure; the bracing structure is fixedly connected to the platform and holds the platform in place; the LED light source is thermally and electrically connected to the LED light strip, which is in turn thermally connected to the reinforcing portion; and the end cap is attached to an end of the lamp tube.

RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 15/386,139, filed Dec. 21, 2016, incorporated byreference herein in its entirety, which is a continuation-in-partapplication of U.S. patent application Ser. No. 15/055,630, filed Feb.28, 2016, incorporated by reference herein in its entirety, which claimsthe benefit of priority under 35 U.S.C. § 119 to the following ChinesePatent Applications, filed with the State Intellectual Property Office(SIPO), each of which is incorporated herein by reference in itsentirety: CN201510104823.3, filed Mar. 10, 2015; CN201510134586.5, filedMar. 26, 2015; CN201510133689.x, filed Mar. 25, 2015; CN201510173861.4,filed Apr. 14, 2015; CN201510193980.6, filed Apr. 22, 2015;CN201510372375.5, filed Jun. 26, 2015; CN201510284720.x, filed May 29,2015; CN201510338027.6, filed Jun. 17, 2015; CN201510315636.x, filedJun. 10, 2015; CN201510406595.5, filed Jul. 10, 2015; CN201510486115.0,filed Aug. 8, 2015; CN201510557717.0, filed Sep. 6, 2015;CN201510595173.7, filed Sep. 18, 2015; CN201510530110.3, filed Aug. 26,2015; CN201510680883.X, filed Oct. 20, 2015; CN201510259151.3, filed May19, 2015; CN201510324394.0, filed Jun. 12, 2015; CN201510373492.3, filedJun. 26, 2015; CN201510482944.1, filed Aug. 7, 2015; CN201510499512.1,filed Aug. 14, 2015; CN201510448220.5, filed Jul. 27, 2015;CN201510483475.5, filed Aug. 8, 2015; CN201510555543.4, filed Sep. 2,2015; CN201510724263.1, filed Oct. 29, 2015; CN201610050944.9, filedJan. 26, 2016; and CN 201510726484.2, filed Oct. 30, 2015. In addition,Chinese Patent Application No.: CN201510075925.7, filed Feb. 12, 2015with the State Intellectual Property Office (SIPO) is also incorporatedherein by reference in its entirety.

If any terms in this application conflict with terms used in anyapplication(s) to which this application claims priority, or termsincorporated by reference into this application or the application(s) towhich this application claims priority, a construction based on theterms as used or defined in this application should be applied.

TECHNICAL FIELD

The invention relates to LED lighting apparatuses or devices. Moreparticularly, the invention relates to LED tube lamps and theirstructures.

BACKGROUND

LED lighting technology is rapidly developing to replace traditionalincandescent and fluorescent lightings. LED tube lamps are mercury-freein comparison with fluorescent tube lamps that need to be filled withinert gas and mercury. Thus, it is not surprising that LED tube lampsare becoming a highly desirable illumination option among differentavailable lighting systems used in homes and workplaces, which used tobe dominated by traditional lighting options such as compact fluorescentlight bulbs (CFLs) and fluorescent tube lamps. Benefits of LED tubelamps include improved durability and longevity and far less energyconsumption. All factors considered, LED tube lamps are typicallyconsidered a cost-effective lighting option.

Typical LED tube lamps have a variety of LED lamp components and drivingcircuits. The LED lamp components include LED chip-packaging elements,light diffusion elements, high-efficiency heat dissipating elements,light reflective boards and light diffusing boards. LED lamps generateconsiderable amount of heat, which, if not properly dissipated, wouldshorten the life of the lamps or even destroy them. Problems includingpower loss, rapid light decay, and short lifetime due to poor heatdissipation are key considerations when improving the performance of theLED illuminating system. Heat dissipation is, therefore, an importantissue when designing LED products.

Nowadays, most LED tube lamps use plastic tubes and metallic elements todissipate heat from the LEDs. The metallic elements are usually exposedand are accessible by users from the outside of the plastic tubes. Thisdesign improves heat dissipation but heightens the risk of electricshocks. If we dispose metallic elements inside the plastic tubes, heatwould be trapped inside the plastic tubes, which may be deformed throughheat. Deformation of the plastic tubes also occurs even when theelements to dissipate heat from the LEDs are not metallic.

Metallic elements for dissipating heat from the LEDs may be made ofaluminum. However, aluminum is too soft to sufficiently support theplastic tubes when deformation of plastic tubes occurs due to the heatas far as the metallic elements disposed inside the plastic tubes areconcerned.

Present ways of using LED lamps such as LED tube lamps to replacetraditional lighting devices (referring mainly to fluorescent lamps)include using a ballast-compatible LED tube lamp. Typically, there is noneed to change the electrical or conductive wirings in traditionallamps, an LED tube lamp can be used to directly replace e.g. afluorescent lamp. Common types of electronic ballast includeinstant-start ballast and program-start ballast. Electronic ballasttypically includes an LC circuit and is designed to match the loadingcharacteristics of a fluorescent lamp in driving the fluorescent lamp.For example, to properly start a fluorescent lamp, the electronicballast provides driving methods respectively corresponding to thefluorescent lamp working as a capacitive device before emitting light,and working as a resistive device upon emitting light. LED is anonlinear component with significantly different characteristics from afluorescent lamp. Therefore, using an LED tube lamp with an electronicballast impacts the design of the LC circuit of the electronic ballast,causing a compatibility problem.

Further, most of the circuit designs for LED tube lamps fail to providesuitable solutions to comply with relevant certification standards andfor better compatibility with the driving structure using an electronicballast originally for a fluorescent lamp. For example, since there areusually no electronic components in a fluorescent lamp, it is easy for afluorescent lamp to be certified under EMI (electromagneticinterference) standards and safety standards for lighting equipment asprovided by Underwriters Laboratories (UL). However, there are aconsiderable number of electronic components in an LED tube lamp.Therefore, consideration of the impacts caused by the layout (structure)of the electronic components is important, resulting in difficulties incomplying with such standards.

Further, the driving of an LED uses a DC driving signal, but the drivingsignal for a fluorescent lamp is a low-frequency, low-voltage AC signalas provided by an AC powerline, a high-frequency, high-voltage AC signalprovided by a ballast, or even a DC signal provided by a battery foremergency lighting applications. Since the voltages and frequencyspectrums of these types of signals differ significantly, simplyperforming a rectification to produce the required DC driving signal inan LED tube lamp does not an LED tube lamp compatible with traditionaldriving systems of a fluorescent lamp.

In addition, for some LED tube lamps, rigid circuit board is typicallyelectrically connected to the end caps by way of wire bonding, in whichthe wires may be easily damaged and even broken due to any move duringmanufacturing, transportation, and usage of the LED tube lamps andtherefore may disable the LED tube lamps. Or, bendable circuit sheet maybe used to electrically connect the LED assembly in the lamp tube andthe power supply assembly in the end cap(s). The length of the lamp tubeduring manufacturing also needs to match for the bendable circuit sheet,and thus the variable factor increases in the manufacture of the lamptube.

The heat generated by the LED tube lamp can be reduced by controllingthe LED illumination and lighting period by an LED driving circuit.However, it is not easy to meet the expected LED illuminationrequirement based on some analog driving manners for two reasons. Therelationship between the LED illumination and the LED current isnon-linear, Moreover, color temperature of some LEDs changes in responseto LED current. Furthermore, heat convection in the lamp tube ishindered, e.g., in some cases, the lamp tube is a closed space, and oncethe LED illumination increases, the lifespan of the LED tube lampshortens because the lifespan of LEDs is sensitive to temperature. Also,some LED driving circuits result in the circuit bandwidth gettingsmaller since the driving voltage/current repeatedly returns between themaximum and minimum. This may limit the minimum conducting period andaffects the driving frequency.

In addition, the LED tube lamp may be provided with power via two endsof the lamp and a user may be easily electric shocked when one end ofthe lamp is already inserted into a terminal of a power supply while theother end is held by the user to reach the other terminal of the powersupply.

Currently applied techniques often fall short when attempting to addressthe above-mentioned worse heat conduction, poor heat dissipation, heatdeformation, electric shock, weak electrical connection, smaller drivingbandwidth, and variable factor in manufacture defects.

SUMMARY

Therefore, it is an object to provide a significantly improved LED tubelamp that dissipates heat more efficiently. It is a further object toprovide an LED tube lamp in which the circuit design is simplified. Itis yet another object to provide an LED tube lamp that is assembledeasily. It is still another object to provide an LED tube lamp thataccommodates a variety of form factors. The electronic components aredisposed on the LED light strip, the end cap, the reinforcing portion oron any combination of the above. The distribution of the set ofelectronic components in a lamp tube depends on a balanced totality ofsuch considerations as heat dissipation, circuit design, easy assemblyand form factor of the lamp tube.

In accordance with an exemplary embodiment, the LED tube lamp comprisesa lamp tube, which includes a light transmissive portion, a reinforcingportion and an end cap; an LED module, which includes an LED lightsource and an LED light strip; and a power supply module, which includesa set of N electronic components operably interconnected to drive theLED light source, wherein: the light transmissive portion is fixedlyconnected to the reinforcing portion; the reinforcing portion includes aplatform and a bracing structure; the bracing structure is fixedlyconnected to the platform and holds the platform in place; the LED lightsource is thermally and electrically connected to the LED light strip,which is in turn thermally connected to the reinforcing portion; the endcap is attached to an end of the lamp tube; the set of N electroniccomponents consists of a first subset of X electronic components, asecond subset of Y electronic components and a third subset of Zcomponents, where N is equal to X+Y+Z; the first subset of X electroniccomponents is disposed on the LED light strip; the second subset of Yelectronic components is disposed on the reinforcing portion; the thirdsubset of Z electronic components is disposed on the end cap; andexactly one of X, Y and Z is equal to N.

In accordance with an exemplary embodiment, the power supply module inthe aforementioned LED tube lamp is spaced as far apart as possible fromthe LED light source.

In accordance with an exemplary embodiment, the power supply module inthe aforementioned LED tube lamp is located as close as possible to theend cap.

In accordance with an exemplary embodiment, X in the aforementioned LEDtube lamp is equal to N.

In accordance with an exemplary embodiment, the LED light strip formsthe platform in the aforementioned LED tube lamp.

In accordance with an exemplary embodiment, the light transmissiveportion is made of plastic; and one of the platform and the LED lightstrip is made of aluminum alloy in the aforementioned LED tube lamp.

In accordance with an exemplary embodiment, the light transmissiveportion and the reinforcing portion define between them a hypotheticalline on a cross section of the lamp tube; and the LED light strip sitson the hypothetical line on the cross section of the lamp tube in theaforementioned LED tube lamp.

In accordance with an exemplary embodiment, the LED light strip in theaforementioned LED tube lamp includes a top surface facing the lighttransmissive portion and a bottom surface facing the reinforcingportion; the LED light source is thermally and electrically connected tothe top surface of the LED light strip; and the set of N electroniccomponents is disposed on at least one of the top surface of the LEDlight strip and the bottom surface of the LED light strip.

In accordance with an exemplary embodiment, the entire set of Nelectronic components is disposed on the top surface of the LED lightstrip in the aforementioned LED tube lamp.

In accordance with an exemplary embodiment, the set of N electroniccomponents in the aforementioned LED tube lamp forms a rectifyingcircuit and a filtering circuit; the rectifying circuit is configured toreceive an external driving signal and to produce a rectified signal;the filtering circuit is coupled to the rectifying circuit on one endand is coupled to the LED light source on the other end; and thefiltering circuit is configured to receive the rectified signal and toproduce a filtered signal, which lights up the LED light source.

In accordance with an exemplary embodiment, the set of N electroniccomponents in the aforementioned LED tube lamp further forms ananti-flickering circuit; and the anti-flickering circuit is coupledbetween the filtering circuit and the LED light source for providingcontinuous power to the LED light source.

In accordance with an exemplary embodiment, the set of N electroniccomponents in the aforementioned LED tube lamp forms a rectifyingcircuit, a filtering circuit and a driving circuit; the rectifyingcircuit is configured to receive an external driving signal and toproduce a rectified signal; the filtering circuit is coupled to therectifying circuit on one end and is coupled to the driving circuit onthe other end; the driving circuit is coupled to the filtering circuiton one end and is coupled to the LED light source on the other end; thefiltering circuit is configured to receive the rectified signal and toproduce a filtered signal; and the driving circuit is configured toreceive the filtered signal and to generate DC power, which lights upthe LED light source.

In accordance with an exemplary embodiment, the LED tube lamp, comprisesa lamp tube, which includes a light transmissive portion, a reinforcingportion and an end cap; an LED light assembly, which includes an LEDlight source and an LED light strip; and a power supply module, whichincludes a set of N electronic components operably interconnected todrive the LED light source, wherein: the light transmissive portion isfixedly connected to the reinforcing portion; the reinforcing portionincludes a platform and a bracing structure; the bracing structure isfixedly connected to the platform and holds the platform in place; theLED light source is thermally and electrically connected to the LEDlight strip, which is in turn thermally connected to the reinforcingportion; the end cap is attached to an end of the lamp tube; the set ofN electronic components consists of a first subset of X electroniccomponents, a second subset of Y electronic components and a thirdsubset of Z components, where N is equal to X+Y+Z; the first subset of Xelectronic components is disposed on the LED light strip; the secondsubset of Y electronic components is disposed on the reinforcingportion; the third subset of Z electronic components is disposed on theend cap; and exactly one of X, Y and Z is equal to 0.

In accordance with an exemplary embodiment, Z is equal to 0 in theaforementioned LED tube lamp.

In accordance with an exemplary embodiment, the LED light strip in theaforementioned LED tube lamp includes a top surface facing the lighttransmissive portion and a bottom surface facing the reinforcingportion; the LED light source is thermally and electrically connected tothe top surface of the LED light strip; and the subset of X electroniccomponents is disposed on at least one of the top surface of the LEDlight strip and the bottom surface of the LED light strip.

In accordance with an exemplary embodiment, the entire subset of Xelectronic components is disposed on the top surface of the LED lightstrip in the aforementioned LED tube lamp.

In accordance with an exemplary embodiment, the reinforcing portion inthe aforementioned LED tube lamp includes a top surface facing the lighttransmissive portion and a bottom surface facing away the lighttransmissive portion; the LED light strip is thermally connected to thetop surface of the reinforcing portion; and the subset of Y electroniccomponents is disposed on at least one of the top surface of thereinforcing portion and the bottom surface of the reinforcing portion.

In accordance with an exemplary embodiment, the entire subset of Yelectronic components is disposed on the top surface of the reinforcingportion in the aforementioned LED tube lamp.

In accordance with an exemplary embodiment, Y is equal to 0 in theaforementioned LED tune lamp.

In accordance with an exemplary embodiment, the LED light strip in theaforementioned LED tube lamp includes a top surface facing the lighttransmissive portion and a bottom surface facing the reinforcingportion; the LED light source is thermally and electrically connected tothe top surface of the LED light strip; and the subset of X electroniccomponents is disposed on at least one of the top surface of the LEDlight strip and the bottom surface of the LED light strip.

In accordance with an exemplary embodiment, the entire subset of Xelectronic components is disposed on the top surface of the LED lightstrip in the aforementioned LED tube lamp.

In accordance with an exemplary embodiment, a biggest electroniccomponent in size of the set of N electronic components is in the subsetof Z electronic components in the aforementioned LED tube lamp.

In accordance with an exemplary embodiment, a biggest electroniccomponent in size of the subset of X electronic components is smallerthan a smallest electronic component in size of the subset of Zelectronic components in the aforementioned LED tube lamp.

In accordance with an exemplary embodiment, the subset of Z electroniccomponents includes at least one of an inductor and an electrolyticcapacitor in the aforementioned LED tube lamp.

In accordance with an exemplary embodiment, the LED tube lamp comprisesa lamp tube, having a light strip disposed inside the lamp tube, an LEDmodule disposed on the light strip, wherein the LED module comprises atleast one LED light source; and a power supply module configured todrive the LED light source for emitting light, wherein all electroniccomponents of the power supply module are disposed on the light strip.

In accordance with an exemplary embodiment, the electronic components inthe aforementioned LED tube lamp comprise a rectifying circuit, afiltering circuit, and a LED driving module, wherein the LED module isdisposed inside the LED driving module, and wherein the LED drivingmodule is coupled to an output terminal of the filtering circuit andconfigured to drive the LED light source for emitting light.

In accordance with an exemplary embodiment, the electronic components inthe aforementioned LED tube lamp further comprise an over voltageprotection circuit configured to clamp signal level of a filtered signalon two filtering output terminals of the filtering circuit.

In accordance with an exemplary embodiment, the over voltage protectioncircuit comprises a voltage stabilization circuit in the aforementionedLED tube lamp.

In accordance with an exemplary embodiment, the voltage stabilizationcircuit in the aforementioned LED tube lamp is a voltage stabilizationdiode configured to clamp a voltage difference, between the twofiltering output terminals of the filtering circuit, on a breakdownvoltage.

In accordance with an exemplary embodiment, a fuse is coupled to aninput terminal of the rectifying circuit in the aforementioned LED tubelamp.

In accordance with an exemplary embodiment, a resistor is coupledbetween output terminals of the rectifying circuit in the aforementionedLED tube lamp.

In accordance with an exemplary embodiment, the aforementioned LED lamptube further comprises a light transmissive portion and a reinforcingportion, the reinforcing portion comprises a platform, and the LEDmodule is disposed on the platform.

In accordance with an exemplary embodiment, the light transmissiveportion is made from plastic, and the platform is an aluminum panel inthe aforementioned LED tube lamp.

In accordance with an exemplary embodiment, the light strip in theaforementioned LED tube lamp is disposed on the aluminum panel and on across section between the light transmissive portion and the reinforcingportion.

In accordance with an exemplary embodiment, the light transmissiveportion in the LED tube lamp is made from plastic, and the light stripis an aluminum panel.

In accordance with an exemplary embodiment, the LED tube lamp comprisesa lamp tube, having a light strip disposed inside the lamp tube, a LEDmodule disposed on the light strip, and the LED module comprising atleast one LED light source, wherein the lamp tube comprises a lighttransmissive portion and a reinforcing portion, the reinforcing portioncomprises a platform, and the LED module is disposed on the platform;and a power supply module configured to drive the LED light source foremitting light, wherein at least some of electronic components of thepower supply module are disposed on the light strip.

In accordance with an exemplary embodiment, the light transmissiveportion is made from plastic, and the platform is an aluminum panel inthe aforementioned LED tube lamp.

In accordance with an exemplary embodiment, the light strip is disposedon the aluminum panel and on a cross section between the lighttransmissive portion and the reinforcing portion in the aforementionedLED tube lamp.

In accordance with an exemplary embodiment, the light transmissiveportion is made from plastic, and the light strip is an aluminum panelin the aforementioned LED tube lamp.

In accordance with an exemplary embodiment, the electronic components inthe aforementioned LED tube lamp comprise a rectifying circuit, afiltering circuit, and a LED driving module, wherein the LED module isdisposed inside the LED driving module, and wherein the LED drivingmodule is coupled to an output terminal of the filtering circuit andconfigured to drive the LED light source for emitting light.

In accordance with an exemplary embodiment, the electronic components inthe aforementioned LED tube lamp further comprise an over voltageprotection circuit configured to clamp signal level of a filtered signalon two filtering output terminals of the filtering circuit.

In accordance with an exemplary embodiment, the over voltage protectioncircuit in the aforementioned LED tube lamp comprises a voltagestabilization circuit, and the voltage stabilization circuit comprises avoltage stabilization diode configured to clamp a voltage difference,between the two filtering output terminals of the filtering circuit, ona breakdown voltage.

Various objects, advantages will become readily apparent from theensuing detailed description, and certain novel features will beparticularly pointed out in the appended claims.

BRIEF DESCRIPTION OF FIGURES

The following detailed descriptions, given by way of example, and notintended to be limiting solely thereto, will be best be understood inconjunction with the accompanying figures:

FIG. 1 is a cross-sectional view of the LED tube lamp with a lighttransmissive portion and a reinforcing portion in accordance with anexemplary embodiment;

FIG. 2 is a cross-sectional view of the LED tube lamp with a bracingstructure in accordance with an exemplary embodiment;

FIG. 3 is a perspective view of the LED tube lamp schematicallyillustrating the bracing structure shown in FIG. 2;

FIG. 4 is a perspective view of the LED tube lamp with a non-circularend cap in accordance with an exemplary embodiment;

FIG. 5 is a cross-sectional view illustrating a vertical rib of the lamptube in accordance with an exemplary embodiment;

FIG. 6 is a cross-sectional view illustrating the bracing structure ofthe lamp tube in accordance with an exemplary embodiment;

FIG. 7 is a cross-sectional view illustrating a ridge, which extends inan axial direction along an inner surface of the lamp tube, inaccordance with an exemplary embodiment;

FIG. 8 is a cross-sectional view illustrating a compartment, which isdefined by the bracing structure of the lamp tube, in accordance with anexemplary embodiment;

FIG. 9 is a cross-sectional view illustrating the bracing structure ofthe lamp tube in accordance with an exemplary embodiment;

FIG. 10 is a perspective view of the lamp tube shown in FIG. 9;

FIG. 11 is a cross-sectional view illustrating the bracing structure ofthe lamp tube in accordance with an exemplary embodiment;

FIG. 12 is a cross-sectional view illustrating the LED light strip witha wiring layer in accordance with an exemplary embodiment;

FIG. 13 is a perspective view of the lamp tube shown in FIG. 12;

FIG. 14 is cross-sectional view illustrating a protection layer disposedon the wiring layer in accordance with an exemplary embodiment;

FIG. 15 is a perspective view of the lamp tube shown in FIG. 14;

FIG. 16 is a perspective view illustrating a dielectric layer disposedon the wiring layer adjacent to the lamp tube in accordance with anexemplary embodiment;

FIG. 17 is a perspective view of the lamp tube shown in FIG. 16;

FIG. 18 is a perspective view illustrating a soldering pad on thebendable circuit sheet of the LED light strip to be joined together withthe printed circuit board of the power supply in accordance with anexemplary embodiment;

FIG. 19 is a planar view illustrating an arrangement of the solderingpads on the bendable circuit sheet of the LED light strip in accordancewith an exemplary embodiment;

FIG. 20 is a planar view illustrating three soldering pads in a row onthe bendable circuit sheet of the LED light strip in accordance with anexemplary embodiment;

FIG. 21 is a planar view illustrating soldering pads sitting in two rowson the bendable circuit sheet of the LED light strip in accordance withan exemplary embodiment;

FIG. 22 is a planar view illustrating four soldering pads sitting in arow on the bendable circuit sheet of the LED light strip in accordancewith an exemplary embodiment;

FIG. 23 is a planar view illustrating soldering pads sitting in a two bytwo matrix on the bendable circuit sheet of the LED light strip inaccordance with an exemplary embodiment;

FIG. 24 is a planar view illustrating through holes formed on thesoldering pads in accordance with an exemplary embodiment;

FIG. 25 is a cross-sectional view illustrating the soldering bondingprocess, which utilizes the soldering pads of the bendable circuit sheetof the LED light strip shown in FIG. 24 taken from side view and theprinted circuit board of the power supply, in accordance with anexemplary embodiment;

FIG. 26 is a cross-sectional view illustrating the soldering bondingprocess, which utilizes the soldering pads of the bendable circuit sheetof the LED light strip shown in FIG. 24, wherein the through hole of thesoldering pads is near the edge of the bendable circuit sheet, inaccordance with an exemplary embodiment;

FIG. 27 is a planar view illustrating notches formed on the solderingpads in accordance with an exemplary embodiment;

FIG. 28 is a cross-sectional view of the LED light strip shown in FIG.27 along the line A-A;

FIG. 29A is a block diagram of an exemplary power supply module in anLED tube lamp according to some embodiments;

FIG. 29B is a block diagram of an exemplary LED lamp according to someembodiments;

FIG. 29C is a block diagram of an exemplary power supply module in anLED tube lamp according to some embodiments;

FIG. 29D is a block diagram of an LED lamp according to someembodiments;

FIG. 30A is a schematic diagram of a rectifying circuit according tosome embodiments;

FIG. 30B is a schematic diagram of a rectifying circuit according tosome embodiments;

FIG. 30C is a schematic diagram of a rectifying circuit according tosome embodiments;

FIG. 30D is a schematic diagram of a rectifying circuit according tosome embodiments;

FIG. 31A is a schematic diagram of a terminal adapter circuit accordingto some embodiments;

FIG. 31B is a schematic diagram of a terminal adapter circuit accordingto some embodiments;

FIG. 31C is a schematic diagram of a terminal adapter circuit accordingto some embodiments;

FIG. 31D is a schematic diagram of a terminal adapter circuit accordingto some embodiments;

FIG. 32A is a block diagram of a filtering circuit according to someembodiments;

FIG. 32B is a schematic diagram of a filtering unit according to someembodiments;

FIG. 32C is a schematic diagram of a filtering unit according to someembodiments;

FIG. 32D is a schematic diagram of a filtering unit according to someembodiments;

FIG. 32E is a schematic diagram of a filtering unit according to someembodiments;

FIG. 33A is a schematic diagram of an LED module according to someembodiments;

FIG. 33B is a schematic diagram of an LED module according to someembodiments;

FIG. 33C is a plan view of a circuit layout of the LED module accordingto some embodiments;

FIG. 33D is a plan view of a circuit layout of the LED module accordingto some embodiments;

FIG. 33E is a plan view of a circuit layout of the LED module accordingto some embodiments;

FIG. 34A is a block diagram of an LED lamp according to someembodiments;

FIG. 34B is a block diagram of a driving circuit according to someembodiments;

FIG. 34C is a schematic diagram of a driving circuit according to someembodiments;

FIG. 34D is a schematic diagram of a driving circuit according to someembodiments;

FIG. 34E is a schematic diagram of a driving circuit according to someembodiments;

FIG. 34F is a schematic diagram of a driving circuit according to someembodiments;

FIG. 34G is a block diagram of a driving circuit according to someembodiments;

FIG. 34H is a graph illustrating the relationship between the voltageVin and the objective current Iout according to certain embodiments;

FIG. 35A is a block diagram of an LED lamp according to someembodiments;

FIG. 35B is a schematic diagram of an anti-flickering circuit accordingto some embodiments;

FIG. 36A is a block diagram of an LED lamp according to someembodiments;

FIG. 36B is a schematic diagram of a protection circuit according tosome embodiments;

FIG. 37A is a block diagram of an LED lamp according to someembodiments;

FIG. 37B is a schematic diagram of a mode switching circuit in an LEDlamp according to some embodiments;

FIG. 37C is a schematic diagram of a mode switching circuit in an LEDlamp according to some embodiments;

FIG. 37D is a schematic diagram of a mode switching circuit in an LEDlamp according to some embodiments;

FIG. 37E is a schematic diagram of a mode switching circuit in an LEDlamp according to some embodiments;

FIG. 37F is a schematic diagram of a mode switching circuit in an LEDlamp according to some embodiments;

FIG. 37G is a schematic diagram of a mode switching circuit in an LEDlamp according to some embodiments;

FIG. 37H is a schematic diagram of a mode switching circuit in an LEDlamp according to some embodiments;

FIG. 37I is a schematic diagram of a mode switching circuit in an LEDlamp according to some embodiment;

FIG. 38A is a block diagram of an LED lamp according to someembodiments;

FIG. 38B is a block diagram of an LED lamp according to someembodiments;

FIG. 38C illustrates an arrangement with a ballast-compatible circuit inan LED lamp according to some embodiments;

FIG. 38D is a block diagram of an LED lamp according to someembodiments;

FIG. 38E is a block diagram of an LED lamp according to someembodiments;

FIG. 38F is a schematic diagram of a ballast-compatible circuitaccording to some embodiments;

FIG. 38G is a block diagram of an exemplary power supply module in anLED lamp according to some embodiments;

FIG. 38H is a schematic diagram of a ballast-compatible circuitaccording to some embodiments;

FIG. 38I illustrates a ballast-compatible circuit according to someembodiments;

FIG. 39A is a block diagram of an LED tube lamp according to someembodiments;

FIG. 39B is a block diagram of an LED tube lamp according to someembodiments;

FIG. 39C is a block diagram of an LED tube lamp according to someembodiments;

FIG. 39D is a schematic diagram of a ballast-compatible circuitaccording to some embodiments, which is applicable to the embodimentsshown in FIGS. 39A and 39B and the described modification thereof;

FIG. 40A is a block diagram of an LED tube lamp according to someembodiments;

FIG. 40B is a schematic diagram of a filament-simulating circuitaccording to some embodiments;

FIG. 40C is a schematic block diagram including a filament-simulatingcircuit according to some embodiments;

FIG. 40D is a schematic block diagram including a filament-simulatingcircuit according to some embodiments;

FIG. 40E is a schematic diagram of a filament-simulating circuitaccording to some embodiments;

FIG. 40F is a schematic block diagram including a filament-simulatingcircuit according to some embodiments;

FIG. 41A is a block diagram of an LED tube lamp according to someembodiments;

FIG. 41B is a schematic diagram of an OVP circuit according to anembodiment;

FIG. 42A is a block diagram of an LED tube lamp according to someembodiments;

FIG. 42B is a block diagram of an LED tube lamp according to someembodiments;

FIG. 42C is a block diagram of a ballast detection circuit according tosome embodiments;

FIG. 42D is a schematic diagram of a ballast detection circuit accordingto some embodiments;

FIG. 42E is a schematic diagram of a ballast detection circuit accordingto some embodiments;

FIG. 43A is a block diagram of an LED tube lamp according to someembodiments;

FIG. 43B is a block diagram of an installation detection moduleaccording to some embodiments;

FIG. 43C is a schematic detection pulse generating module according tosome embodiments;

FIG. 43D is a schematic detection determining circuit according to someembodiments;

FIG. 43E is a schematic detection result latching circuit according tosome embodiments; and

FIG. 43F is a schematic switch circuit according to some embodiments.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present disclosure now will be described more fully hereinafter withreference to the accompanying drawings, in which various embodiments areshown. The invention may, however, be embodied in many different formsand should not be construed as limited to the example embodiments setforth herein. These example embodiments are just that—examples—and manyimplementations and variations are possible that do not require thedetails provided herein. It should also be emphasized that thedisclosure provides details of alternative examples, but such listing ofalternatives is not exhaustive. Furthermore, any consistency of detailbetween various examples should not be interpreted as requiring suchdetail—it is impracticable to list every possible variation for everyfeature described herein. The language of the claims should bereferenced in determining the requirements of the invention.

In the drawings, the size and relative sizes of layers and regions maybe exaggerated for clarity. Like numbers refer to like elementsthroughout. Though different figures show variations of exemplaryembodiments, these figures are not necessarily intended to be mutuallyexclusive from each other. Rather, as will be seen from the context ofthe detailed description below, certain features depicted and describedin different figures can be combined with other features from otherfigures to result in various embodiments, when taking the figures andtheir description as a whole.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items and may beabbreviated as “/”. As used herein, the term “and/or” includes any andall combinations of one or more of the associated listed items. Also,the term “exemplary” is intended to refer to an example or illustration.

Although the figures described herein may be referred to using languagesuch as “one embodiment,” or “certain embodiments,” these figures, andtheir corresponding descriptions are not intended to be mutuallyexclusive from other figures or descriptions, unless the context soindicates. Therefore, certain aspects from certain figures may be thesame as certain features in other figures, and/or certain figures may bedifferent representations or different portions of a particularexemplary embodiment.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements, components, regions,layers and/or sections, these elements, components, regions, layersand/or sections should not be limited by these terms. Unless the contextindicates otherwise, these terms are only used to distinguish oneelement, component, region, layer or section from another element,component, region, layer or section, for example as a naming convention.Thus, a first element, component, region, layer or section discussedbelow in one section of the specification could be termed a secondelement, component, region, layer or section in another section of thespecification or in the claims without departing from the teachings ofthe present invention. In addition, in certain cases, even if a term isnot described using “first,” “second,” etc., in the specification, itmay still be referred to as “first” or “second” in a claim in order todistinguish different claimed elements from each other.

It will be further understood that the terms “comprises” and/or“comprising,” or “includes” and/or “including” when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

It will be understood that when an element is referred to as being“connected” or “coupled” to, “in contact with,” or “on” another element,it can be directly connected or coupled to, in contact with, or on theother element or intervening elements may be present. In contrast, whenan element is referred to as being “directly connected,” “directlycoupled,” in “direct contact with,” or “directly on” to another element,there are no intervening elements present. Other words used to describethe relationship between elements should be interpreted in a likefashion (e.g., “between” versus “directly between,” “adjacent” versus“directly adjacent,” etc.). However, the term “contact,” as used hereinrefers to direct contact (i.e., touching) unless the context indicatesotherwise.

Embodiments described herein will be described referring to plan viewsand/or cross-sectional views by way of ideal schematic views.Accordingly, the exemplary views may be modified depending onmanufacturing technologies and/or tolerances. Therefore, the disclosedembodiments are not limited to those shown in the views, but includemodifications in configuration formed on the basis of manufacturingprocesses. Therefore, regions exemplified in figures may have schematicproperties, and shapes of regions shown in figures may exemplifyspecific shapes of regions of elements to which aspects of the inventionare not limited.

Although corresponding plan views and/or perspective views of somecross-sectional view(s) may not be shown, the cross-sectional view(s) ofdevice structures illustrated herein provide support for a plurality ofdevice structures that extend along two different directions as would beillustrated in a plan view, and/or in three different directions aswould be illustrated in a perspective view. The two different directionsmay or may not be orthogonal to each other. The three differentdirections may include a third direction that may be orthogonal to thetwo different directions. The plurality of device structures may beintegrated in a same electronic device. For example, when a devicestructure (e.g., a memory cell structure or a transistor structure) isillustrated in a cross-sectional view, an electronic device may includea plurality of the device structures (e.g., memory cell structures ortransistor structures), as would be illustrated by a plan view of theelectronic device. The plurality of device structures may be arranged inan array and/or in a two-dimensional pattern.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper” and the like, may be used herein for ease of description todescribe one element's or feature's relationship to another element(s)or feature(s) as illustrated in the figures. It will be understood thatthe spatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the term “below” can encompass both an orientation ofabove and below. The device may be otherwise oriented (rotated 90degrees or at other orientations) and the spatially relative descriptorsused herein interpreted accordingly.

Terms such as “same,” “planar,” or “coplanar,” as used herein whenreferring to orientation, layout, location, shapes, sizes, amounts, orother measures do not necessarily mean an exactly identical orientation,layout, location, shape, size, amount, or other measure, but areintended to encompass nearly identical orientation, layout, location,shapes, sizes, amounts, or other measures within acceptable variationsthat may occur, for example, due to manufacturing processes. The term“substantially” may be used herein to reflect this meaning.

As used herein, items described as being “electrically connected” areconfigured such that an electrical signal can be passed from one item tothe other. Therefore, a passive electrically conductive component (e.g.,a wire, pad, internal electrical line, etc.) physically connected to apassive electrically insulative component (e.g., a prepreg layer of aprinted circuit board, an electrically insulative adhesive connectingtwo devices, an electrically insulative underfill or mold layer, etc.)is not electrically connected to that component. Moreover, items thatare “directly electrically connected,” to each other are electricallyconnected through one or more passive elements, such as, for example,wires, pads, internal electrical lines, through vias, etc. As such,directly electrically connected components do not include componentselectrically connected through active elements, such as transistors ordiodes.

Components described as thermally connected or in thermal communicationare arranged such that heat will follow a path between the components toallow the heat to transfer from the first component to the secondcomponent. Simply because two components are part of the same device orpackage does not make them thermally connected. In general, componentswhich are heat-conductive and directly connected to otherheat-conductive or heat-generating components (or connected to thosecomponents through intermediate heat-conductive components or in suchclose proximity as to permit a substantial transfer of heat) will bedescribed as thermally connected to those components, or in thermalcommunication with those components. On the contrary, two componentswith heat-insulative materials therebetween, which materialssignificantly prevent heat transfer between the two components, or onlyallow for incidental heat transfer, are not described as thermallyconnected or in thermal communication with each other. The terms“heat-conductive” or “thermally-conductive” do not apply to a particularmaterial simply because it provides incidental heat conduction, but areintended to refer to materials that are typically known as good heatconductors or known to have utility for transferring heat, or componentshaving similar heat conducting properties as those materials.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It willbe further understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and/orthe present application, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein. In addition,unless the context indicates otherwise, steps described in a particularorder need not occur in that order.

Referring to FIG. 1, in accordance with an exemplary embodiment, an LEDtube lamp comprises a lamp tube 1 and an LED light assembly. The lamptube 1 includes a light transmissive portion 105 and a reinforcingportion 107. The reinforcing portion 107 is fixedly connected to thelight transmissive portion 105.

The LED light assembly is disposed inside the lamp tube 1 and includesan LED light source 202 and an LED light strip 2. The LED light sourceis thermally and electrically connected to the LED light strip 2, whichis in turn thermally connected to the reinforcing portion 107. Thoughonly one LED light source 202 is shown, a plurality of light sources 202may be arranged on the LED light strip 2. For example, light sources 202may be arranged in one or more rows extending along a length directionof the LED light strip 2, which may extend along a length direction ofthe lamp tube 1. In addition, a light source, as discussed herein, mayrefer to a single light emitting diode (LED), to a set of LEDs includinga plurality of LEDs, or to one or more sets of LEDs (e.g., it may referto the entire set of LEDs on the light strip 2). Heat generated by theLED light source 202 is first transmitted to the LED light strip 2 andthen to the reinforcing portion 107 before egressing the lamp tube 1.Thermal connection is achieved with thermally conductive tapes orconventional mechanical fasteners such as screws aided by thermal greaseto eliminate air gaps from interface areas.

Typically, the lamp tube 1 has a shape of an elongated cylinder, whichis a straight structure. However, the lamp tube 1 can take any curvedstructure such as a ring or a horseshoe. The cross section of the lamptube 1 defines, typically, a circle, or not as typically, an ellipse ora polygon. Alternatively, the cross section of the lamp tube 1 takes anirregular shape depending on the shapes of, respectively, the lighttransmissive portion 105 and the reinforcing portion 107 and on themanner the two portions interconnect to form the lamp tube 1.

The lamp tube 1 is a glass tube, a plastic tube or a tube made of anyother suitable material or combination of materials. In someembodiments, a plastic lamp tube is made from light transmissiveplastic, thermally conductive plastic or a combination of both. Thelight transmissive plastic may be one of translucent polymer matricessuch as polymethyl methacrylate, polycarbonate, polystyrene,poly(styrene-co-methyl methacrylate) and a mixture thereof. In someembodiments, the strength and elasticity of thermally conductive plasticis enhanced by bonding a plastic matrix with glass fibers. In anembodiment, an outer shell of lamp tube includes a plurality of layersmade from distinct materials. For example, the lamp tube may include aplastic tube coaxially sheathed by a glass tube.

In an embodiment, the light transmissive portion 105 is made from lighttransmissive plastic, and the reinforcing portion 107 is made fromthermally conductive plastic. Injection molding may be used forproducing the light transmissive portion 105 in a first piece and forproducing the reinforcing portion 107 in a separate second piece. Thefirst piece and the second piece may be configured to be clippedtogether, buckled together, glued together or otherwise fixedlyinterconnected to form the lamp tube 1. Alternatively, injection moldingis used for producing the lamp tube 1, which includes the lighttransmissive portion 105 and the reinforcing portion 107, in an integralpiece by feeding two types of plastic materials into a molding process.In an alternative embodiment, the reinforcing portion is made of metalhaving good thermal conductivity such as an aluminum alloy and copperalloy.

Respective shapes of the light transmissive portion 105 and thereinforcing portion 107, how the two portions 105, 107 interconnect toform the lamp tube 1 and, particularly, the respective proportions ofthe two portions 105, 107 in the lamp tube depend on a desired totalityof considerations such as field angle, heat dissipation efficiency andstructural strength. A wider field angle—potentially at the expense ofheat dissipation capability and structural strength—is achieved when theproportion of the light transmissive portion increases 105 in relationto that of the reinforcing portion 107. By contrast, the lamp tubebenefits from an increased proportion of the reinforcing portion 107 inrelation to that of the light transmissive portion in such ways asbetter heat dissipation and rigidity but potentially loses field angle.

In some embodiments, the reinforcing portion 107 includes a plurality ofprotruding parts. In other embodiments, a plurality of protruding partsare disposed on the surface of the LED light strip 2 that is not coveredby the LED light assembly. Like fins on a heatsink, each protruding partboosts heat dissipation by increasing the surface area of thereinforcing portion 107 and the LED light strip 2. The protruding partsare disposed equidistantly, or alternatively, not equidistantly.

Staying on FIG. 1, the lamp tube 1 has a shape of a circular cylinder.For example, a cross section of the lamp tube 1 defines a hypotheticalcircle. A line H-H cuts the circle horizontally into two equal halvesalong a diameter of the circle. A cross section of the lighttransmissive portion 105 defines an upper segment on the circle. A crosssection of the reinforcing portion 107 defines a lower segment on thecircle. A dividing line 104 parallel to the line H-H is shared by thetwo segments. In this embodiment, the dividing line 104 sits exactly onthe line H-H. Consequently, the area of the upper segment is the same asthat of the lower segment. In one embodiment, the cross section of thelight transmissive portion 105 has a same area as that of thereinforcing portion 107.

In an alternative embodiment, the dividing line 104 is spaced apart fromthe line H-H. For example, when the dividing line 104 is below the lineH-H, the upper segment, which encompasses the light transmissiveportion, has a greater area than the lower segment, which encompassesthe reinforcing portion. The lamp tube, which includes an enlarged lighttransmissive portion, is thus configured to achieve a field angle widerthan 180 degrees; however, other things equal, the lamp tube surrenderssome heat dissipation capability, structural strength or both due to adiminished reinforcing portion 107. By contrast, the lamp tube 1 mayhave an enlarged reinforcing portion 107 and a diminished lighttransmissive portion 105 if the dividing line rises above the line H-H.Other things equal, the lamp tube 1, now having an enlarged reinforcingportion 107, is configured to exhibit higher heat dissipationcapability, structural strength or both; however, the field angle of thelamp tube 1 will dwindle due to diminished dimensions of the lighttransmissive portion 105.

According to certain embodiments, the LED tube lamp is configured toconvert bright spots coming from the LED light source(s) into an evenlydistributed luminous output. In an embodiment, a light diffusion layeris disposed on an inner surface of the lamp tube 1 or an outer surfaceof the lamp tube 1. In another embodiment, a diffusion laminate isdisposed over the LED light source 202. In yet another embodiment, thelamp tube 1 has a glossy outer surface and a frosted inner surface. Theinner surface is rougher than the outer surface. The roughness Ra of theinner surface may be, for example, from 0.1 to 40 μm. In someembodiments, roughness Ra of the inner surface may be from 1 to 20 μm.Controlled roughness of the surface is obtained mechanically by a cuttergrinding against a workpiece, deformation on a surface of a workpiecebeing cut off or high frequency vibration in the manufacturing system.Alternatively, roughness is obtained chemically by etching a surface.Depending on the luminous effect the lamp tube 1 is designed to produce,a suitable combination of amplitude and frequency of a roughened surfaceis provided by a matching combination of workpiece and finishingtechnique.

In alternative embodiments, the diffusion layer is in the form of anoptical diffusion coating, which is composed of any one of calciumcarbonate, halogen calcium phosphate and aluminum oxide, or anycombination thereof. When the optical diffusion coating is made from acalcium carbonate with suitable solution, an excellent light diffusioneffect and transmittance to exceed 90% can be obtained.

In the embodiment, the composition of the diffusion layer in form of theoptical diffusion coating includes calcium carbonate, strontiumphosphate (e.g., CMS-5000, white powder), thickener, and a ceramicactivated carbon (e.g., ceramic activated carbon SW—C, which is acolorless liquid). Specifically, such an optical diffusion coating onthe inner circumferential surface of the glass tube has an averagethickness ranging between about 20 to about 30 μm. A light transmittanceof the diffusion layer using this optical diffusion coating is about90%. Generally speaking, the light transmittance of the diffusion layerranges from 85% to 96%. In addition, this diffusion layer can alsoprovide electrical isolation for reducing risk of electric shock to auser upon breakage of the lamp tube 1. Furthermore, the diffusion layerprovides an improved illumination distribution uniformity of the lightoutputted by the LED light sources 202 such that the light canilluminate the back of the light sources 202 and the side edges of thebendable circuit sheet so as to avoid the formation of dark regionsinside the lamp tube 1 and improve the illumination comfort. In anotherpossible embodiment, the light transmittance of the diffusion layer canbe 92% to 94% while the thickness ranges from about 200 to about 300 μm.

In another embodiment, the optical diffusion coating can also be made ofa mixture including calcium carbonate-based substance, some reflectivesubstances like strontium phosphate or barium sulfate, a thickeningagent, ceramic activated carbon, and deionized water. The mixture iscoated on the inner circumferential surface of the glass tube and has anaverage thickness ranging between about 20 to about 30 μm. In view ofthe diffusion phenomena in microscopic terms, light is reflected byparticles. The particle size of the reflective substance such asstrontium phosphate or barium sulfate will be much larger than theparticle size of the calcium carbonate. Therefore, adding a small amountof reflective substance in the optical diffusion coating can effectivelyincrease the diffusion effect of light.

In other embodiments, halogen calcium phosphate or aluminum oxide canalso serve as the main material for forming the diffusion layer. Theparticle size of the calcium carbonate is about 2 to 4 μm, while theparticle size of the halogen calcium phosphate and aluminum oxide areabout 4 to 6 μm and 1 to 2 μm, respectively. When the lighttransmittance is required to be 85% to 92%, the required averagethickness for the optical diffusion coating mainly having the calciumcarbonate is about 20 to about 30 μm, while the required averagethickness for the optical diffusion coating mainly having the halogencalcium phosphate may be about 25 to about 35 μm, the required averagethickness for the optical diffusion coating mainly having the aluminumoxide may be about 10 to about 15 μm. However, when the required lighttransmittance is up to 92% and even higher, the optical diffusioncoating mainly having the calcium carbonate, the halogen calciumphosphate, or the aluminum oxide must be thinner.

The main material and the corresponding thickness of the opticaldiffusion coating can be decided according to the place for which thelamp tube 1 is used and the light transmittance required. It is to benoted that the higher the light transmittance of the diffusion layer isrequired, the more apparent the grainy visual of the light sources is.

In an embodiment, the LED tube lamp is configured to reduce internalreflectance by applying a layer of anti-reflection coating to an innersurface of the lamp tube 1. The coating has an upper boundary, whichdivides the inner surface of the lamp tube and the anti-reflectioncoating, and a lower boundary, which divides the anti-reflection coatingand the air in the lamp tube 1. Light waves reflected by the upper andlower boundaries of the coating interfere with one another to reducereflectance. The coating is made from a material with a refractive indexof a square root of the refractive index of the light transmissiveportion 105 of the lamp tube 1 by vacuum deposition. Tolerance of thecoating's refractive index is ±20%. The thickness of the coating ischosen to produce destructive interference in the light reflected fromthe interfaces and constructive interference in the correspondingtransmitted light. In an additional embodiment, reflectance is furtherreduced by using alternating layers of a low-index coating and ahigher-index coating. The multi-layer structure is designed to, whensetting parameters such as combination and permutation of layers,thickness of a layer, refractive index of the material, give lowreflectivity over a broad band that covers at least 60%, or in someembodiments, 80% of the wavelength range beaming from the LED lightsource 202. In some embodiments, three successive layers ofanti-reflection coatings are applied to an inner surface of the lamptube 1 to obtain low reflectivity over a wide range of frequencies. Thethicknesses of the coatings are chosen to give the coatings opticaldepths of, respectively, one half, one quarter and one half of thewavelength range coming from the LED light source 202. Dimensionaltolerance for the thickness of the coating is set at ±20%.

Turning to FIG. 2, in accordance with an exemplary embodiment, the crosssection of the lamp tube 1, unlike that of the cylindrical lamp tube 1in FIG. 1, approximates an arc sitting on a flange of an I-beam. Thelamp tube 1 includes a light transmissive portion 105 and a reinforcingportion 107. A cross section of the light transmissive portion 105defines an upper segment on a hypothetical circle. A line H-H cuts thecircle horizontally into two equal halves along a diameter of thecircle. The reinforcing portion 107 includes a platform 107 a and abracing structure 107 b. The platform 107 a has an upper surface and alower surface. The LED light assembly is disposed on the upper surfaceof the platform 107 a. The bracing structure 107 b is fixedly connectedto the platform 107 a and holds the platform 107 a in place. The bracingstructure 107 b includes a horizontal rib, a vertical rib, a curvilinearrib or a combination of ribs selected from the above. The dimensions ofthe platform 107 a, the horizontal rib and the vertical rib, theirquantities and the manner they interconnect depend on a desired totalityof considerations such as heat dissipation efficiency and structuralstrength. In the embodiment, the cross section of the reinforcingportion 107 approximates that of an I-beam. The platform 107 a, thevertical rib and the horizontal rib correspond to, respectively, theupper flange, the web and the bottom flange of the I-beam. In someembodiments, the bracing structure 107 b may include only one verticalrib and only one horizontal rib.

A dividing line 104 parallel to the line H-H is shared by the uppersegment and the upper flange. In the embodiment, the dividing line sitsbelow the line H-H. Consequently, the upper segment constitutes themajority of the hypothetical circle. The light transmissive portion 105may be configured to generate a field angle wider than 180 degrees. Inan alternative embodiment, the dividing line sits on or above the lineH-H. For example, when the dividing line rises above the line H-H, theupper segment, which encompasses the light transmissive portion, nowconstitutes less than half of the hypothetical circle. The lamp tube 1,which has an enlarged reinforcing portion 107, may be configured forbetter heat dissipation and structural strength; however, other thingsequal, the lamp tube 1 loses some luminous filed due to a diminishedlight transmissive portion 105.

In an embodiment, a surface on which the LED light assembly sits—e.g.the upper surface of the platform—is configured to further reflect thelight reflected from the inner surface of the lamp tube 1. The surfaceon which the LED light assembly sits is coated with a reflective layer.Alternatively, the surface is finished to exhibit a reflectance of 80 to95%, or preferably, 85 to 90%. Finishing is performed mechanically,chemically or by fluid jet. Mechanical finishing buffs a surface byremoving peaks from the surface with an abrasive stick, a wool polishingwheel or a sandpaper. A surface treated this way has a roughness Ra aslow as 0.008 to 1 μm. Chemical finishing works by dissolving peaks of asurface faster than troughs of the surface with a chemical agent. Fluidjet finishing uses a high-speed stream of slurry to accurately removenanometers of material from a surface. The slurry is prepared by addingparticles such as silicon carbide powder to a fluid capable of beingpumped under relatively low pressure.

Turning to FIG. 3, in accordance with an exemplary embodiment, the LEDtube lamp further comprises an end cap 3, which is fixedly connected toan end of the lamp tube 1. The end cap 3 is made from plastic, metal ora combination of both. The end cap 3 and the lamp tube 1 are latchedtogether, buckled together or otherwise mechanically fastened to oneanother. Alternatively, the two parts are glued together with hot-meltadhesive, e.g. a silicone matrix with a thermal conductivity of at least0.7 Wm−1K−1.

Typically, the end cap 3 has a shape of a cylinder, and the crosssection of the end cap 3 may define a circle. Alternatively, the crosssection of the end cap 3 takes an irregular shape depending on theshapes of, respectively, the light transmissive portion and thereinforcing portion and on the manner the two portions and the end cap 3interconnect to form the LED tube lamp. Regardless of the shape of theend cap 3, the cross section of the end cap 3 encloses all or only apart of the cross section of the reinforcing portion 107 of the lamptube 1. In the embodiment shown in FIG. 3, the end cap 3 defines acircular cylinder whose cross section encloses, entirely, the crosssections of, respectively, the light transmissive portion 105 and thereinforcing portion 107. The cross section of the lamp tube 1approximates a segment, defined by the light transmissive portion 105,sitting on an upper flange of a hypothetical I-beam, defined by thereinforcing portion 107. A cross section of an inner surface of the endcap 3 defines a hypothetical circle. The hypothetical circle shares asame arc of the hypothetical segment defined by an outer surface of thelight transmissive portion 105. The I-beam is enclosed, entirely, by thehypothetical circle.

In an alternative embodiment shown in FIG. 4, the cross section of theend cap 3 encloses all of the cross section of the light transmissiveportion 105 but only a part of that of the reinforcing portion 107. Across section of the inner surface of the end cap 3 defines a samehypothetical segment defined by an outer surface of the lighttransmissive portion 105. However, only the upper flange of thehypothetical I-beam is enclosed by the hypothetical segment, but thelower flange and the web are not.

In some embodiments, an end of the LED light assembly extends to the endcap 3 as shown in FIGS. 3 and 4. In other embodiments, an end of the LEDlight assembly recedes from the end cap 3.

The bracing structure 107 b may be made of metal or plastic. The metalmay be pure metal, metal alloy or combination of pure metal and metalalloy with different stiffness. Similarly, the plastic may includematerials with various stiffness. Specifically, the plastic lamp tubemay include only one bracing structure with one stiffness or two bracingstructures with various stiffness.

When only one bracing structure is adopted, the material of the bracingstructure may be metal, metal alloy, or plastic, and the ratio of thecross-sectional area of the bracing structure to the cross-sectionalarea of the lamp tube is from 1:3 to 1:30. In some embodiments, theratio of the cross-sectional area of the bracing structure to thecross-sectional area of the lamp tube is from 1:5 to 1:10.

When more than one bracing structures with different stiffness areadopted, the bracing structure is made of one of metal, metal alloy andplastic. In one embodiment, when two bracing structures with differentstiffness are adopted, the ratio of the cross-sectional area of thebracing structure with greater stiffness to the cross-sectional area ofthe other bracing structure is from 0.001:1 to 100:1. The ratio of thecross-sectional area of the bracing structure with greater stiffness tothe cross-sectional area of the lamp tube 1 is from 1:20 to 1:300.

In view of the bracing structure made of metal, the lamp tube revealsthe following combinations of materials and parts on the cross sectionof the lamp tube perpendicular to the longitudinal axis of the lamptube: (1) a lamp tube made of plastic, a first bracing structure made ofa metal with a first stiffness, and a second bracing structure, such asa maintaining stick, made of a metal with a second stiffness differentfrom the first stiffness; (2) a lamp tube made of plastic and a singlebracing structure made of metal and/or metal alloy; or (3) a lamp tubemade of plastic, a first bracing structure made of metal, and a secondbracing structure, such as a maintaining stick, made of metal alloy.Similarly, various types of plastics with different stiffness can beused to serve as the bracing structures mentioned above in someembodiments. The materials used for bracing structures have differentstiffness; but the materials are not limited. For example, metal ormetal alloy and plastic could serve as materials for different bracingstructures without departing from the spirit of the embodiments.Additionally, the bracing structure is made from a material having agreater stiffness than the material from which the lamp tube is made.

In some embodiments, the lamp tube includes a first end cap fixedlyconnected to a first end of the lamp tube and a second end cap fixedlyconnecting to a second end of the lamp tube. The first end cap isdimensionally larger—e.g. from 20% to 70% larger—than the second endcap.

Shifting to FIG. 5, in accordance with an exemplary embodiment, thecross section of the lamp tube 1 approximates an arc sitting on a flangeof a hypothetical T-beam. The cross section of the reinforcing portion107 approximates that of the T-beam. The platform 107 a and the verticalrib correspond to, respectively, the flange and the web of the T-beam.For instance, in some embodiments, the bracing structure 107 b mayinclude only one vertical rib but no horizontal rib. When the crosssection of the end cap 3 encloses, entirely, the cross sections of,respectively, the light transmissive portion 105 and the reinforcingportion 107, other things equal, the vertical rib in a T-beam structure(FIG. 5) has a greater length than the vertical rib in an I-beamstructure (FIG. 3).

Turning to FIG. 6, in accordance with an exemplary embodiment, thebracing structure 107 b includes a vertical rib and a curvilinear ribbut no horizontal rib. The cross section of the lamp tube 1 defines ahypothetical circle. A cross section of the light transmissive portion105 defines an upper arc on the circle. A cross section of thecurvilinear rib defines a lower arc on the circle. A cross section ofthe platform 107 a and the vertical rib approximates that of ahypothetical T-beam. All three ends of the T-beam sit on the lower arc.The ratio of the length of the vertical rib to the diameter of the lamptube 1 depends on a desired totality of considerations such as fieldangle, heatsinking efficiency and structural strength. The ratio of thelength of the vertical rib to the diameter of the lamp tube 1 may be,for example, from 1:1.2 to 1:30. In some embodiments, the ratio of thelength of the vertical rib to the diameter of the lamp tube 1 may befrom 1:3 to 1:10.

Turing to FIG. 7, in accordance with an exemplary embodiment, the lamptube 1 further includes a ridge 235. The ridge 235 extends in an axialdirection along an inner surface of the lamp tube 1. The ridge 235 is anelongated hollow structure unbroken from end to end, or alternatively,broken at intervals. Injection molding is used for producing thereinforcing portion 230 and the ridge 235 in an integral piece. Theposition of the ridge 235 in relation to the line H-H bisecting thehypothetical circle defined by the lamp tube 1 depends on, as elaboratedearlier, a desired totality of considerations such as field angle,heatsink efficiency and structural strength.

In an embodiment, the lamp tube 1 further includes a ridge 235 and amaintaining stick 2351. The maintaining stick 2351 is, likewise, anelongated structure, which is unbroken from end to end, oralternatively, broken at intervals, and which fills up the space insidethe ridge 235. The maintaining stick 2351 is made of thermallyconductive plastic, or alternatively, metal. The metal is one of carbonsteel, cast steel, nickel chrome steel, alloyed steel, ductile iron,grey cast iron, white cast iron, rolled manganese bronze, rolledphosphor bronze, cold-drawn bronze, rolled zinc, aluminum alloy andcopper alloy. The material from which the maintaining stick 2351 is madeis chosen to provide the LED tube lamp with a combination of heatdissipation capability and structural strength that is otherwise absentfrom other parts of the lamp tube 1. In an embodiment, the maintainingstick 2351 is made from a different material than the material fromwhich the LED light strip 2 or the reinforcing portion 107 is made. Forexample, when the LED light strip 2 or the reinforcing portion 107 ofthe lamp tube 1 is made from a metal having superior heat dissipationcapability but insufficient stiffness, e.g. aluminum panel, themaintaining stick 2351 is made from a metal stiffer than aluminum tosupply more structural strength. In some embodiments, the ratio of thevolume of heatsinking-oriented metal to the volume of stiffness-orientedmetal in a lamp tube 1 is from 0.001:1 to 100:1. In other embodiments,the ratio is from 0.1:1 to 10:1. In some embodiments, the ratio of thecross-sectional area of the maintaining stick 2351 to that of the lamptube 1 is from 1:20 to 1:100. In other embodiments, the ratio is from1:50 to 1:100.

In some embodiments, the lamp tube 1 includes a light transmissiveportion and a reinforcing portion. In other embodiments, a ridge issubstituted for the reinforcing portion. In some exemplary embodiments,the lamp tube 1 may include a light transmissive portion and a ridge,but no reinforcing portion. In an improved embodiment, the lamp tube 1further includes a maintaining stick that fills up the space inside theridge.

The outer surface of the reinforcing portion forms an outer surface ofthe lamp tube 1, as the embodiments in FIGS. 1-6. Alternatively, theouter surface of the reinforcing portion forms none of the outer surfaceof the lamp tube, as the embodiments in FIGS. 7-11. Where thereinforcing portion 107 is disposed entirely inside the lamp tube 1, thereinforcing portion 107 rests on the inner surface of the lamp tube 1along a substantially uninterrupted interface, as the embodiment in FIG.8; or alternatively, along an interrupted interface, as the embodimentsin FIGS. 7, 9-11.

Focusing on FIG. 7, in accordance with an exemplary embodiment, a firstcompartment is defined by the reinforcing portion 107 and the innersurface of the lamp tube 1. A second compartment is defined by the LEDlight strip 2 and the inner surface of the lamp tube 1. Likewise, inFIG. 8, a compartment is defined by the platform 231, the horizontal riband the curvilinear rib. In some embodiments, a ridge is disposed insidethe compartment for great structural strength. In other embodiments, amaintaining stick fills up the space inside the hollow structure of theridge.

The length of the reinforcing portion, on which the LED light assemblyis disposed, in the vertical direction in relation to the diameter ofthe lamp tube depends on the field angle the lamp tube is designed toproduce. In the embodiment shown in FIG. 7, the ratio of the distance(D) between the LED light assembly and the dome of the lamp tube 1 tothe diameter of the lamp tube 1 may be, for example, from 0.25 to 0.9.In some exemplary embodiments, the ratio of the distance (D) between theLED light assembly and the dome of the lamp tube 1 to the diameter ofthe lamp tube 1 may be from 0.33 to 0.75.

Turning to FIG. 8, in accordance with an exemplary embodiment, the lamptube further includes a pair of protruding bars 236. The protruding bar236 extends in an axial direction along an inner surface of the lamptube 1 and is configured to form a guiding channel inside the lamp tube1. The reinforcing portion 107 is connected to the lamp tube 1 bysliding the reinforcing portion 107 into the guiding channel. In theembodiment, a cross section of an inner surface of the lamp tube 1defines a hypothetical circle. A cross section of the curvilinear rib230 defines a lower arc on the circle. A cross section of the platform231 and the vertical rib 233 approximates that of a hypothetical T-beam.All three ends of the T-beam sit on the lower arc. The pair ofprotruding bars 236 and the inner surface of the lamp tube 1 form theguiding channel in the lamp tube 1. The cross section of the guidingchannel is defined by the flange of the T-beam and the lower arc. Thereinforcing portion 107 may be configured to fit snugly into the guidingchannel.

Turning to FIGS. 9 and 10, in accordance with an exemplary embodiment,the reinforcing portion 230 includes a plurality of vertical ribs 233.The vertical rib 233 is fixedly connected to the inner surface of thelamp tube 1 on one end and to the LED light strip 2 on the other end.The LED light assembly may be spaced apart from the inner surface of theplastic lamp tube 1. The plastic lamp tube 1 is protected from heatgenerated by the LED light assembly because the heat is taken away fromthe lamp tube 1 by the plurality of the vertical ribs 233. A crosssection of the lamp tube 1 cuts through an LED light source 202, a firstvertical rib 233 connected to an upper surface of the LED lightassembly, a second vertical rib 233 connected to a lower surface of theLED light assembly or any combination of the above. In some embodiments,the LED light assembly, the first vertical rib 233 and the secondvertical rib 233 may be aligned with one another, or alternatively, maybe staggered. In an embodiment, the second vertical rib 233 connected tothe lower surface of the LED light assembly is an unbroken structureextending along the longitudinal axis of the lamp tube 1 for better heatdissipation and more structural strength. In FIG. 10, the plurality offirst vertical ribs 233 are spaced apart from one another like an arrayof pillars. However, the second vertical rib 233 extends uninterruptedlybetween the lower surface of the LED light assembly and the lamp tube 1like a wall.

Turning to FIG. 11, in accordance with an exemplary embodiment, thereinforcing portion 230 further includes a platform. The vertical rib233 is fixedly connected to, instead of the LED light assembly, theplatform on one end and to the inner surface on the other end. Thevertical ribs 233 and the platform may be one integral structure. TheLED light assembly is thermally connected to an upper surface of theplatform.

The position of the LED light strip 2 inside the lamp tube 1—i.e. thelength of the first vertical rib 233 and the length of the secondvertical rib 233—is chosen in light of a desired totality of factorssuch as field angle, heat-dissipating capability and structuralstrength. In FIGS. 9 and 11, the ratio of the distance (H) between theLED light strip 2 and the dome of the lamp tube 1 to the diameter of thelamp tube 1 may be, for example, from 0.25 to 0.9. In some embodiments,the ratio of the distance (H) between the LED light strip 2 and the domeof the lamp tube 1 to the diameter of the lamp tube 1 may be from 0.33to 0.75.

In an embodiment, the LED light strip is made from flexible substratematerial. Referring to FIGS. 12 and 13, in accordance with an exemplaryembodiment, the flexible LED light strip 2 includes a wiring layer 2 a.The wiring layer 2 a is an electrically conductive layer, e.g. ametallic layer or a layer of copper wire, and is electrically connectedto the power supply. The LED light source 202 is disposed on andelectrically connected to a first surface of the wiring layer 2 a.Turning to FIGS. 16 and 17, the LED light strip 2 further includes adielectric layer 2 b. A dielectric layer 2 b is disposed on a secondsurface of the wiring layer 2 a. The dielectric layer 2 b has adifferent surface area from the wiring layer 2 a. The LED light source202 is disposed on a surface of the wiring layer 2 a which is oppositeto the other surface of the wiring layer 2 a which is adjacent to thedielectric layer 2 b. The wiring layer 2 a can be a metal layer or alayer having wires such as copper wires.

In an embodiment, the LED light strip 2 further includes a protectionlayer over the wiring layer 2 a and the dielectric layer 2 b. Theprotection layer is made from one of solder resists such as liquidphotoimageable.

In another embodiment, as shown in FIGS. 14 and 15, the outer surface ofthe wiring layer 2 a or the dielectric layer 2 b (i.e. the two-layeredstructure) may be covered with a circuit protective layer 2 c made ofink for resisting soldering and increasing reflectivity. Alternatively,the dielectric layer 2 b is omitted and the wiring layer 2 a is directlybonded to the inner circumferential surface of the lamp tube (i.e. theone-layered structure), and the outer surface of the wiring layer 2 a iscoated with the circuit protective layer 2 c. As shown in FIGS. 14 and15, the circuit protective layer 2 c has openings such that the LEDlight sources 202 are electrically connected to the wiring layer 2 a.Whether the one-layered or the two-layered structure is used, thecircuit protective layer 2 c can be adopted. The bendable circuit sheetis a one-layered structure including just one wiring layer 2 a, or atwo-layered structure including one wiring layer 2 a and one dielectriclayer 2 b, and may be more bendable or flexible to curl when comparedwith conventional three-layered flexible substrates (one dielectriclayer sandwiched by two wiring layers). Consequently, the bendablecircuit sheet of the LED light strip 2 can be installed in a lamp tubewith a customized shape or non-tubular shape, and fitly mounted to theinner surface of the lamp tube. In some embodiments, the bendablecircuit sheet may be closely mounted to the inner surface of the lamptube. In addition, using fewer layers of the bendable circuit sheetimproves heat dissipation and lowers costs for materials.

In some embodiments, any type of power supply 5 can be electricallyconnected to the LED light strip 2 by means of traditional wire bondingtechnique, in which a metal wire has an end connected to the powersupply 5 while having the other end connected to the LED light strip 2.Furthermore, the metal wire is wrapped with an electrically insulatingtube to protect a user from being electrically shocked. However, thebonded wires tend to be easily broken during transportation and cantherefore cause quality issues. A portion of a power supply 5 isdepicted in FIG. 18, for example, and certain other figures. The powersupply and a power supply module will be discussed in greater detailbelow.

In still another embodiment, the connection between the power supply 5and the LED light strip is accomplished via soldering (e.g., using tin),rivet bonding, or welding. One way to secure the LED light strip 2 is toprovide the adhesive sheet at one side thereof and attach the LED lightstrip 2 to the inner surface of the lamp tube 1 via the adhesive sheet.Two ends of the LED light strip 2 are either fixed to or detached fromthe inner surface of the lamp tube 1.

In case where two ends of the LED light strip 2 are fixed to the innersurface of the lamp tube 1, a bendable circuit sheet of the LED lightstrip 2 may be provided with a female plug and the power supply isprovided with a male plug to accomplish the connection between the LEDlight strip 2 and the power supply 5. In this case, the male plug of thepower supply is inserted into the female plug to establish electricalconnection.

In a case where two ends of the LED light strip 2 are not attached fromthe inner surface of the lamp tube and that the LED light strip 2 isconnected to the power supply 5 via wire-bonding, any movement insubsequent transportation is likely to cause the bonded wires to break.Therefore, in some embodiments, the connection between the light strip 2and the power supply 5 could be accomplished via direct soldering. Forexample, the ends of the LED light strip 2 including the bendablecircuit sheet can be arranged to pass over the strengthened transitionregion and be directly solder bonded to an output terminal of the powersupply 5 such that the product quality is improved without using wires.In this way, the female plug and the male plug respectively provided forthe LED light strip 2 and the power supply 5 are no longer needed.

Referring to FIG. 18, an output terminal of the printed circuit board ofthe power supply 5 may have soldering pads “a” provided with an amountof tin solder with a thickness sufficient to later form a solder joint.Correspondingly, the ends of the LED light strip 2 may have solderingpads “b”. The soldering pads “a” on the output terminal of the printedcircuit board of the power supply 5 are soldered to the soldering pads“b” on the LED light strip 2 via the tin solder on the soldering pads“a”. The soldering pads “a” and the soldering pads “b” may be face toface during soldering such that the connection between the LED lightstrip 2 and the printed circuit board of the power supply 5 is the mostfirm. However, this kind of soldering may involve a thermo-compressionhead pressing on the rear surface of the LED light strip 2 and heatingthe solder, e.g., the LED light strip 2 intervenes between thethermo-compression head and the solder. This may cause reliabilityproblems. Referring to FIG. 24, a through hole is formed in each of thesoldering pads “b” on the LED light strip 2 to allow the soldering pads“b” to overlay the soldering pads “b” without being face-to-face. Inthis case, the thermo-compression head directly presses solder on thesoldering pads “a” on a surface of the printed circuit board of thepower supply 5 when the soldering pads “a” and the soldering pads “b”are vertically aligned.

Referring again to FIG. 18, the LED light strip 2 includes a fixedportion 22 and a freely extending portion 21, which has a first end anda second end. The fixed portion 22 is, from end to end, attached to theinner surface of the lamp tube 1 and is thus immovable in relation tothe lamp tube 1. The freely extending portion 21 is not attached toanything except at the ends. For example, two ends of the LED lightstrip 2 detached from the inner surface of the lamp tube 1 are formed asfreely extending portions 21, while most of the LED light strip 2 isattached and secured to the inner surface of the lamp tube 1. The firstend of the freely extending portion 21, which includes the soldering pad“b” described above, is fixedly and electrically connected to theprinted circuit board of the power supply 5. The second end of thefreely extending portion 21 is fixedly and electrically connected to(and may be integrally formed with) a near end of the fixed portion 22.In some embodiments, the length of the curved segment defined by thefreely extending portion 21 is substantially the same as the lineardistance between the ends of the freely extending portion 21. In otherembodiments, the length of the curved segment defined by the freelyextending portion 21 is longer than the linear distance between the endsof the freely extending portion 21, allowing the freely extendingportion 21 to adaptively deform in response to the actual distance fromthe first end of the freely extending portion 21 to the second end ofthe freely extending portion 21. The effect of errors during assembly ormanufacturing is thus mitigated.

In this embodiment, during the connection of the LED light strip 2 andthe power supply 5, the soldering pads “b” and the soldering pads “a”and the LED light sources 202 are on surfaces facing toward the samedirection and the soldering pads “b” on the LED light strip 2 are eachformed with a through hole “e” as shown in FIG. 24 such that thesoldering pads “b” and the soldering pads “a” communicate with eachother via the through holes “e.” When the freely extending portions 21are deformed due to contraction or curling up, the soldered connectionof the printed circuit board of the power supply 5 and the LED lightstrip 2 exerts a lateral tension on the power supply 5. Furthermore, thesoldered connection of the printed circuit board of the power supply 5and the LED light strip 2 also exerts a downward tension on the powersupply 5 when compared with the situation where the soldering pads “a”of the power supply 5 and the soldering pads “b” of the LED light strip2 are face to face. This downward tension on the power supply 5 comesfrom the tin solders inside the through holes “e” and forms a strongerand more secure electrical connection between the LED light strip 2 andthe power supply 5.

Referring to FIG. 19, in one embodiment, the soldering pads “b” of theLED light strip 2 are two separate pads to electrically connect thepositive and negative electrodes of the bendable circuit sheet of theLED light strip 2, respectively. The size of the soldering pads “b” maybe, for example, about 3.5×2 mm2. The printed circuit board of the powersupply 5 is correspondingly provided with soldering pads “a” havingreserved solders (e.g., tin solders) and the height of the tin solderssuitable for subsequent automatic soldering bonding process may begenerally, for example, about 0.1 to 0.7 mm, in some embodiments 0.3 to0.5 mm. In some exemplary embodiments, the height of the tin solderssuitable for a subsequent automatic solder bonding process is about 0.4mm. An electrically insulating through hole “c” is formed between thetwo soldering pads “b” to isolate and prevent the two soldering padsfrom electrically shorting during soldering. Furthermore, an extrapositioning opening “d” may also be provided behind the electricallyinsulating through hole “c” to allow an automatic soldering machine toquickly locate the soldering pads “b”.

There is at least one soldering pad “b” for separately connecting to thepositive and negative electrodes of the LED light sources 202. Toachieve scalability and compatibility, the amount of the soldering pads“b” on each end of the LED light strip 2 may be more than one such astwo, three, four, or more than four. When there is only one solderingpad “b” provided at each end of the LED light strip 2, the two ends ofthe LED light strip 2 are electrically connected to the power supply 5to form a loop, and various electrical components can be used. Forexample, a capacitator may be replaced by an inductor to perform currentregulation. Referring to FIGS. 20 to 23, when each end of the LED lightstrip 2 has three soldering pads, the third soldering pad can be pad isgrounded; when each end of the LED light strip 2 has four solderingpads, the fourth soldering pad can be used as a signal input terminal.Correspondingly, the power supply 5 should have a same number ofsoldering pads “a” as that of the soldering pads “b” on the LED lightstrip 2. As long as electrical short between the soldering pads “b” canbe prevented, the soldering pads “b” should be arranged according to thedimension of the actual area for disposition, for example, threesoldering pads can be arranged in a row or two rows. In otherembodiments, the number of the soldering pads “b” on the bendablecircuit sheet of the LED light strip 2 may be reduced by rearranging thecircuits on the bendable circuit sheet of the LED light strip 2. Theless the number of the soldering pads, the easier the fabricationprocess becomes. On the other hand, a greater number of soldering padsmay improve and secure the electrical connection between the LED lightstrip 2 and the output terminal of the power supply 5.

Referring to FIG. 24, in another embodiment, each soldering pads “b” isformed with a through hole “e” having a diameter generally of about 1 to2 mm. In some embodiments of about 1.2 to 1.8 mm. In yet someembodiments of about 1.5 mm. The through hole “e” communicates thesoldering pad “a” with the soldering pad “b” so that the tin solder onthe soldering pads “a” passes through the through holes “e” and finallyreach the soldering pads “b.” A smaller through holes “e” would make itdifficult for the tin solder to pass. The tin solder accumulates aroundthe through holes “e” upon exiting the through holes “e” and condense toform a solder ball “g” with a larger diameter than that of the throughholes “e” upon condensing. Such a solder ball “g” functions as a rivetto further increase the stability of the electrical connection betweenthe soldering pads “a” on the power supply 5 and the soldering pads “b”on the LED light strip 2.

Referring to FIGS. 25 to 26, in other embodiments, when a distance fromthe through hole “e” to the side edge of the LED light strip 2 is lessthan 1 mm, the tin solder may pass through the through hole “e” toaccumulate on the periphery of the through hole “e”, and extra tinsolder may spill over the soldering pads “b” to reflow along the sideedge of the LED light strip 2 and join the tin solder on the solderingpads “a” of the power supply 5. The tin solder then condenses to form astructure like a rivet to firmly secure the LED light strip 2 onto theprinted circuit board of the power supply 5 such that reliable electricconnection is achieved. Referring to FIG. 27 and FIG. 28, in anotherembodiment, the through hole “e” is replaced by a notch “f” formed atthe side edge of the soldering pads “b” for the tin solder to easilypass through the notch “f” and accumulate on the periphery of the notch“f” and to form a solder ball with a larger diameter than that of thenotch “e” upon condensing. Such a solder ball may be formed like aC-shape rivet to enhance the secure capability of the electricallyconnecting structure.

The abovementioned through hole “e” or notch “f” might be formed inadvance of soldering or formed by direct punching with athermo-compression head during soldering. The portion of thethermo-compression head for touching the tin solder may be flat,concave, or convex, or any combination thereof. The portion of thethermo-compression head for restraining the object to be soldered suchas the LED light strip 2 may be strip-like or grid-like. The portion ofthe thermo-compression head for touching the tin solder does notcompletely cover the through hole “e” or the notch “f” to make sure thatthe tin solder passes through the through hole “e” or the notch “f”. Theportion of the thermo-compression head being concave may function as acompartment to receive the solder ball.

The power supply 5, which may include a power supply module, includes aset of electronic components operatively interconnected to drive the LEDlight source. The electronic components are disposed on the LED lightstrip, on the end cap, on the reinforcing portion, or on any combinationof the above. For example, the power supply module may include allelectronic components of the LED tube lamp for supplying power to theLEDs that form the LED light source, such as all electronic componentsof a rectifying circuit, a filtering circuit, a driving circuit (ifany), and an over voltage protection circuit (if any). As discussedherein a power supply or electronic components described as being “onthe end cap” may be on a circuit board fixedly attached to an end cap.In this case, some of all of this power supply or these components maybe disposed in the end cap. The distribution of the set of power supplymodule electronic components in a lamp tube depends on a desiredtotality of such considerations as heat dissipation, circuit design,easy assembly and form factor of the lamp tube. In one embodiment, theentire set of the electronic components is disposed on exactly one ofthe LED light strip, the reinforcing portion, and the end cap. When theentire set of electronic components is lumped together on exactly onepart of the lamp tube, the assembly of the tube lamp is made easier andthe design of circuit simplified. When the entire set of electroniccomponents is disposed on the LED light strip (e.g., fixedly attached toa surface of the LED light strip, and/or embedded as part of the LEDlight strip), a dedicated dielectric layer—which would be otherwisenecessary if an electronic component is disposed on a metallic object(e.g. the reinforcing portion made of aluminum alloy)—is no longerneeded because the LED light strip is built on a non-conductivesubstrate. When the entire set of electronic components is disposed onthe reinforcing portion (e.g., fixedly attached to a surface of thereinforcing portion), heat coming from the power supply module is takenaway faster because the reinforcing portion is close by to drain theenergy. When the entire set of electronic components is disposed on theend cap, (e.g., on a rigid circuit board fixedly attached to the end cap(e.g., to be supported by the end cap), and which electronic componentsmay be in the end cap, heat coming from the power supply module is lesslikely to impact the LED light source because the power supply module iskept spaced apart from the LED light source.

In another embodiment, the entire set of electronic components for thepower supply module is disposed on exactly two of the LED light strip,the reinforcing portion and the end cap. For example, when the entireset of electronic components is distributed to the reinforcing portionand the end cap but nowhere else, the LED light strip is amenable to areplaceable design without entangling the rest of the lamp tube. Whenthe entire set of electronic components is distributed to the LED lightstrip and the reinforcing portion but nowhere else, the end cap isdetachable without entangling the rest of the lamp tube. When the entireset of electronic components is distributed to the LED light strip andthe end cap but nowhere else, the reinforcing potion is amenable to aminimal design—without having to carry the power supply module—to dropthe weight of the lamp tube and cut cost.

When the set of electronic components is disposed on the end cap and onat least one of the LED light strip and the reinforcing portion, thespace inside the lamp tube is optimally used if components with a biggerdimension—e.g. the inductor and the electrolytic capacitor—are disposedin the end cap. In an embodiment, any one of the electronic componentsdisposed in the end cap is bigger than an electronic component disposedelsewhere in the lamp tube. For example, at least one of an inductor andan electrolytic capacitor is disposed in the end cap but the rest ofsmaller electronic components are disposed elsewhere.

In yet another embodiment, the entire set of electronic components forthe power supply module is distributed to each one of the LED lightstrip, the reinforcing portion and the end cap. For example, thecomponents that generate the most heat may sit on the reinforcingportion for quick heatsinking. The bigger components may be lodged inthe end cap to save space. The rest of the components may stay on theLED light strip.

When a set of electronic components is disposed on an object, the set ofelectronic components may be disposed on a same side of the object(e.g., same surface of the object). Alternatively, the set of electroniccomponents may be disposed on both sides of the object (e.g., oppositesurfaces of the object). Assembly can be made easier when all componentssit on a same side of the object than when on both sides of the objectbecause the latter entails extra structures such as through holes andconnection wiring. However, having components on both sides potentiallyincreases the space for circuit layouts on the LED light strip otherwiseavailable when all components are laid out on a same side. For example,in one embodiment, when a set of electronic components is disposed onthe LED light strip, the set of electronic components is disposed on asame side of the LED light strip. Alternatively, the set of electroniccomponents is disposed on both sides of the LED light strip. The LEDlight strip includes a top surface facing the light transmissive portionand a bottom surface facing the reinforcing portion. In an embodiment,the entire set of electronic components is disposed on the top surfaceof the LED light strip. In another embodiment, the entire set ofelectronic components is disposed on the bottom surface of the LED lightstrip. In yet another embodiment, an electronic component is disposed onthe top surface of the LED light strip and an electronic component isdisposed on the bottom surface of the LED light strip. Likewise, in oneembodiment, when a set of electronic components is disposed on thereinforcing portion, the set of electronic components is disposed on asame side of the reinforcing portion. Alternatively, the set ofelectronic components may be disposed on both sides of the reinforcingportion. The reinforcing portion includes a top surface facing the lighttransmissive portion and a bottom surface facing away the lighttransmissive portion. In an embodiment, the entire set of electroniccomponents is disposed on the top surface of the reinforcing portion. Inanother embodiment, the entire set of electronic components is disposedon the bottom surface of the reinforcing portion. In yet anotherembodiment, an electronic component is disposed on the top surface ofthe reinforcing portion and an electronic component is disposed on thebottom surface of the reinforcing portion.

The electronic components for the power supply module discussed hereininclude components that affect (e.g., change, generate, transform,store, or regulate) voltage, current, or signals, and do not refer tosimple wires for transmitting a signal. If a total of N power supplyelectronic components are used in an LED tube lamp, different amounts(e.g., from zero to N) of the electronic components can be disposed ondifferent ones of the LED light strip, the reinforcing portion, and theend cap. These different values may be referred to herein as X, Y, andZ.

In certain embodiments, to mitigate the impact of heat generated by thepower supply module on the LED light source, the LED light source (e.g.,the entire set of LEDs included in the LED light strip, or a first LEDor set of LEDs nearest the power supply) is spaced as far apart from thepower supply module as possible. For example, if the lamp tube has apredetermined length (L1), the LED light source take up a length of L12(e.g., the LEDs are arranged in a line have a length L2 from the firstto last LED), the power supply components are disposed at one end of thelamp tube at a distance L3 from the end of the lamp tube, and the otherend of the lamp tube requires at least a distance of L4 for any wiringand/or electronic components, then the predetermined length L1 of thelamp tube may be said to have a length of L2+L3+L4+L5, where L5 is theremaining free space in the lamp tube. So in one embodiment, the LEDlight source (e.g., set of LEDs on the light strip) is disposed theentire distance L5 away from the nearest power supply components. Insome embodiments, the power supply module is disposed as close to theend cap as possible. For example, it may be disposed in the end cap, oron the light strip with only a minimal amount of space between the powersupply module and the end cap. In other embodiments, the power supplymodule is disposed in the end cap, at an end of the LED light strip orboth.

In an embodiment, the power supply module is disposed in the end cap. Inanother embodiment, the power supply module is disposed on the junctionbetween the light strip and the end cap. In yet another embodiment, thepower supply module is disposed on the light strip and adjacent to theend cap without a gap between the end of the end cap adjacent the lighttube and the power supply module. In still another embodiment, the powersupply module is disposed on the light strip with a small gap betweenthe end of the end cap adjacent the light tube and the power supplymodule (e.g., in the longitudinal direction of the LED tube lamp). Forexample, the small gap may be a small percentage of the length of thepower supply module (e.g., less than 10%).

The power supply module 5 is electrically coupled to the LED light strip2 and certain features and applications of the related power supplyassembly are described below. It is noticeable that the circuits and theassemblies mentioned below may be all disposed on the reinforcingportion in the lamp tube to increase the heat dissipating area andefficiency, simplify the circuit design in the end cap, and provide aneasier control for the length of the lamp tube in manufacturing. Or,some of them are kept in the end cap (e.g. resistors, or capacitors, orthe components with smaller volume or smaller power consumption, thecomponents generating less heat or having better heat resistant) and theothers are disposed on the reinforcing portion (e.g. chips, inductors,transistors, or the components with bigger volume, the componentsgenerating much heat or having poor heat resistant) so as to increasethe heat dissipating area and efficiency and simplify the circuit designin the end cap. The invention is not limited to the disclosedembodiments.

In some embodiments, for example, the circuits and the assembliesdisposed on the reinforcing portion in the lamp tube may be implementedby surface mount components. Some of the circuits and the assemblies maybe disposed on the LED light strip and then electrically connected tothe circuit(s) kept in the end cap via male-female plug or wire withinsulating coating/layer for achieving the isolation effect. Or, thecircuits and the assemblies related to the power supply may all bedisposed on the LED light strip to reduce the reserved length of the LEDlight strip, which is used for connecting to other circuit board(s), andalso to reduce the allowable error length and omit the process forelectrically connecting two or more circuit boards, so that the lengthsof the lamp tube and the LED light strip could be controlled moreprecisely. The circuits and the assemblies and the LEDs may be disposedon the same or different side of the reinforcing portion. In someembodiments, the circuits and the assemblies and the LEDs may bedisposed on the same side to reduce the process of making throughhole(s) on the reinforcing portion for electrically connection. Theinvention is not limited to the disclosed embodiments.

Next, examples of the circuit design and using of the power supplymodule are described below.

FIG. 29A is a block diagram of a power supply system for an LED tubelamp according to an embodiment. Referring to FIG. 29A, an AC powersupply 508 is used to supply an AC supply signal, and may be an ACpowerline with a voltage rating, for example, from 100 to 277 volts anda frequency rating, for example, of 50 or 60 Hz. A lamp driving circuit505 receives and then converts the AC supply signal into an AC drivingsignal as an external driving signal. Lamp driving circuit 505 may befor example an electronic ballast used to convert the AC powerline intoa high-frequency high-voltage AC driving signal. Common types ofelectronic ballast include instant-start ballast, program-start orrapid-start ballast, etc., which may all be applicable to the LED tubelamp. The voltage of the AC driving signal is likely to be higher than300 volts, and is in some embodiments in the range of from 400 to 700volts. The frequency of the AC driving signal may be higher than 10 kHz. In some embodiments, the frequency of the AC driving signal may bein the range of from 20 k to 50 k Hz. The LED tube lamp 500 receives anexternal driving signal and is thus driven to emit light. In oneembodiment, the external driving signal comprises the AC driving signalfrom lamp driving circuit 505. In one embodiment, LED tube lamp 500 isin a driving environment in which it is power-supplied at its one endcap having two conductive pins 501, 502, which are coupled to lampdriving circuit 505 to receive the AC driving signal. The two conductivepins 501 and 502 may be electrically connected to, either directly orindirectly, the lamp driving circuit 505.

It is worth noting that lamp driving circuit 505 may be omitted and istherefore depicted by a dotted line. In one embodiment, if lamp drivingcircuit 505 is omitted, AC power supply 508 is directly connected topins 501 and 502, which then receive the AC supply signal as an externaldriving signal.

In addition to the above use with a single-end power supply, LED tubelamp 500 may instead be used with a dual-end power supply to one pin ateach of the two ends of an LED lamp tube.

FIG. 29B is a block diagram of an LED lamp according to one embodiment.Referring to FIG. 29B, the power supply module of the LED lamp includesa rectifying circuit 510 and a filtering circuit 520, and may alsoinclude some components of an LED lighting module 530. Rectifyingcircuit 510 is coupled to pins 501 and 502 to receive and then rectifyan external driving signal, so as to output a rectified signal at outputterminals 511 and 512. The external driving signal may be the AC drivingsignal or the AC supply signal described with reference to FIG. 29A, ormay even be a DC signal. The nature of the external driving signal willnot impact on the way the LED lamp is otherwise implemented. Filteringcircuit 520 is coupled to the first rectifying circuit for filtering therectified signal to produce a filtered signal. For instance, filteringcircuit 520 is coupled to terminals 511 and 512 to receive and thenfilter the rectified signal, so as to output a filtered signal at outputterminals 521 and 522. LED lighting module 530 is coupled to filteringcircuit 520, to receive the filtered signal for emitting light. Forinstance, LED lighting module 530 may be a circuit coupled to terminals521 and 522 to receive the filtered signal and thereby to drive an LEDlight source (not shown) in LED lighting module 530 to emit light.Details of these operations are described in below descriptions ofcertain embodiments.

It is worth noting that although there are two output terminals 511 and512 and two output terminals 521 and 522 in embodiments of these Figs.,in practice the number of ports or terminals for coupling betweenrectifying circuit 510, filtering circuit 520, and LED lighting module530 may be one or more depending on the signal transmission between thecircuits or devices.

In addition, the power supply module of the LED lamp described in FIG.29B, and embodiments of the power supply module of an LED lamp describedbelow, may each be used in the LED tube lamp 500 in FIG. 29A, and mayinstead be used in any other type of LED lighting structure having twoconductive pins used to conduct power, such as LED light bulbs, personalarea lights (PAL), plug-in LED lamps with different types of bases (suchas types of PL-S, PL-D, PL-T, PL-L, etc.).

FIG. 29C is a block diagram of a power supply system for an LED tubelamp according to an embodiment. Referring to FIG. 29C, an AC powersupply 508 is used to supply an AC supply signal. A lamp driving circuit505 receives and then converts the AC supply signal into an AC drivingsignal. An LED tube lamp 500 receives an AC driving signal from lampdriving circuit 505 and is thus driven to emit light. In thisembodiment, LED tube lamp 500 is power-supplied at its both end capsrespectively having two pins 501 and 502 and two pins 503 and 504, whichare coupled to lamp driving circuit 505 to concurrently receive the ACdriving signal to drive an LED light source (not shown) in LED tube lamp500 to emit light. AC power supply 508 may be the AC powerline, and lampdriving circuit 505 may be a stabilizer or an electronic ballast.

FIG. 29D is a block diagram of an LED lamp according to an embodiment.Referring to FIG. 29D, the power supply module of the LED lamp includesa rectifying circuit 510, a filtering circuit 520, and a rectifyingcircuit 540, and may also include some components of an LED lightingmodule 530. Rectifying circuit 510 is coupled to pins 501 and 502 toreceive and then rectify an external driving signal conducted by pins501 and 502. Rectifying circuit 540 is coupled to pins 503 and 504 toreceive and then rectify an external driving signal conducted by pins503 and 504. Therefore, the power supply module of the LED lamp mayinclude two rectifying circuits 510 and 540 configured to output arectified signal at output terminals 511 and 512. Filtering circuit 520is coupled to terminals 511 and 512 to receive and then filter therectified signal, so as to generate a filtered signal at outputterminals 521 and 522. LED lighting module 530 is coupled to terminals521 and 522 to receive the filtered signal and thereby to drive an LEDlight source (not shown) in LED lighting module 530 to emit light.

The power supply module of the LED lamp in this embodiment of FIG. 29Dmay be used in LED tube lamp 500 with a dual-end power supply in FIG.29C. It is worth noting that since the power supply module of the LEDlamp comprises rectifying circuits 510 and 540, the power supply moduleof the LED lamp may be used in LED tube lamp 500 with a single-end powersupply in FIG. 29A, to receive an external driving signal (such as theAC supply signal or the AC driving signal described above). The powersupply module of an LED lamp in this embodiment and other embodimentsherein may also be used with a DC driving signal.

FIG. 30A is a schematic diagram of a rectifying circuit according to anembodiment. Referring to FIG. 30A, rectifying circuit 610 includesrectifying diodes 611, 612, 613, and 614, configured to full-waverectify a received signal. Diode 611 has an anode connected to outputterminal 512, and a cathode connected to pin 502. Diode 612 has an anodeconnected to output terminal 512, and a cathode connected to pin 501.Diode 613 has an anode connected to pin 502, and a cathode connected tooutput terminal 511. Diode 614 has an anode connected to pin 501, and acathode connected to output terminal 511.

When pins 501 and 502 receive an AC signal, rectifying circuit 610operates as follows. During the connected AC signal's positive halfcycle, the AC signal is received from pin 501, diode 614, and outputterminal 511 in sequence, and later output through output terminal 512,diode 611, and pin 502 in sequence. During the connected AC signal'snegative half cycle, the AC signal is received from pin 502, diode 613,and output terminal 511 in sequence, and later output through outputterminal 512, diode 612, and pin 501 in sequence. Therefore, during theconnected AC signal's full cycle, the positive pole of the rectifiedsignal produced by rectifying circuit 610 remains at output terminal511, and the negative pole of the rectified signal remains at outputterminal 512. Accordingly, the rectified signal produced or output byrectifying circuit 610 is a full-wave rectified signal.

When pins 501 and 502 are coupled to a DC power supply to receive a DCsignal, rectifying circuit 610 operates as follows. When pin 501 iscoupled to the anode of the DC supply and pin 502 to the cathode of theDC supply, the DC signal is input through pin 501, diode 614, and outputterminal 511 in sequence, and later output through output terminal 512,diode 611, and pin 502 in sequence. When pin 501 is coupled to thecathode of the DC supply and pin 502 to the anode of the DC supply, theDC signal is input through pin 502, diode 613, and output terminal 511in sequence, and later output through output terminal 512, diode 612,and pin 501 in sequence. Therefore, no matter what the electricalpolarity of the DC signal is between pins 501 and 502, the positive poleof the rectified signal produced by rectifying circuit 610 remains atoutput terminal 511, and the negative pole of the rectified signalremains at output terminal 512.

Therefore, rectifying circuit 610 in this embodiment can output orproduce a proper rectified signal regardless of whether the receivedinput signal is an AC or DC signal.

FIG. 30B is a schematic diagram of a rectifying circuit according to anembodiment. Referring to FIG. 30B, rectifying circuit 710 includesrectifying diodes 711 and 712, configured to half-wave rectify areceived signal. Diode 711 has an anode connected to pin 502, and acathode connected to output terminal 511. Diode 712 has an anodeconnected to output terminal 511, and a cathode connected to pin 501.Output terminal 512 may be omitted or grounded depending on actualapplications.

Next, exemplary operation(s) of rectifying circuit 710 is described asfollows.

In one embodiment, during a received AC signal's positive half cycle,the electrical potential at pin 501 is higher than that at pin 502, sodiodes 711 and 712 are both in a cutoff state as being reverse-biased,making rectifying circuit 710 not outputting a rectified signal. Duringa received AC signal's negative half cycle, the electrical potential atpin 501 is lower than that at pin 502, so diodes 711 and 712 are both ina conducting state as being forward-biased, allowing the AC signal to beinput through diode 711 and output terminal 511, and later outputthrough output terminal 512, a ground terminal, or another end of theLED tube lamp not directly connected to rectifying circuit 710.Accordingly, the rectified signal produced or output by rectifyingcircuit 710 is a half-wave rectified signal.

FIG. 30C is a schematic diagram of a rectifying circuit according to anembodiment. Referring to FIG. 30C, rectifying circuit 810 includes arectifying unit 815 and a terminal adapter circuit 541. In thisembodiment, rectifying unit 815 comprises a half-wave rectifier circuitincluding diodes 811 and 812 and configured to half-wave rectify. Diode811 has an anode connected to an output terminal 512, and a cathodeconnected to a half-wave node 819. Diode 812 has an anode connected tohalf-wave node 819, and a cathode connected to an output terminal 511.Terminal adapter circuit 541 is coupled to half-wave node 819 and pins501 and 502, to transmit a signal received at pin 501 and/or pin 502 tohalf-wave node 819. By means of the terminal adapting function ofterminal adapter circuit 541, rectifying circuit 810 allows of two inputterminals (connected to pins 501 and 502) and two output terminals 511and 512.

Next, in certain embodiments, rectifying circuit 810 operates asfollows.

During a received AC signal's positive half cycle, the AC signal may beinput through pin 501 or 502, terminal adapter circuit 541, half-wavenode 819, diode 812, and output terminal 511 in sequence, and lateroutput through another end or circuit of the LED tube lamp. During areceived AC signal's negative half cycle, the AC signal may be inputthrough another end or circuit of the LED tube lamp, and later outputthrough output terminal 512, diode 811, half-wave node 819, terminaladapter circuit 541, and pin 501 or 502 in sequence.

It's worth noting that terminal adapter circuit 541 may comprise aresistor, a capacitor, an inductor, or any combination thereof, forvoltage/current regulation or limiting, types of protection,current/voltage regulation, etc. These functions are described below.

In practice, rectifying unit 815 and terminal adapter circuit 541 areinterchangeable in position (as shown in FIG. 30D), without altering thefunction of half-wave rectification. FIG. 30D is a schematic diagram ofa rectifying circuit according to an embodiment. Referring to FIG. 30D,diode 811 has an anode connected to pin 502 and diode 812 has a cathodeconnected to pin 501. A cathode of diode 811 and an anode of diode 812are connected to half-wave node 819. Terminal adapter circuit 541 iscoupled to half-wave node 819 and output terminals 511 and 512. During areceived AC signal's positive half cycle, the AC signal may be inputthrough another end or circuit of the LED tube lamp, and later outputthrough output terminal 512 or 512, terminal adapter circuit 541,half-wave node 819, diode 812, and pin 501 in sequence. During areceived AC signal's negative half cycle, the AC signal may be inputthrough pin 502, diode 811, half-wave node 819, terminal adapter circuit541, and output node 511 or 512 in sequence, and later output throughanother end or circuit of the LED tube lamp.

It is worth noting that terminal adapter circuit 541 in embodimentsshown in FIGS. 30C and 30D may be omitted and is therefore depicted by adotted line. If terminal adapter circuit 541 of FIG. 30C is omitted,pins 501 and 502 will be coupled to half-wave node 819. If terminaladapter circuit 541 of FIG. 30D is omitted, output terminals 511 and 512will be coupled to half-wave node 819.

Rectifying circuit 510 as shown and explained in FIGS. 30A-D can be therectifying circuit 540 shown in FIG. 29D, as having pins 503 and 504 forconducting instead of pins 501 and 502.

Next, an explanation follows as to choosing embodiments and theircombinations of rectifying circuits 510 and 540, with reference to FIGS.29B and 29D.

Rectifying circuit 510 in embodiments shown in FIG. 29B may comprise therectifying circuit 610 in FIG. 30A.

Rectifying circuits 510 and 540 in embodiments shown in FIG. 29D mayeach comprise any one of the rectifying circuits in FIGS. 30A-D, andterminal adapter circuit 541 in FIGS. 30C-D may be omitted withoutaltering the rectification function used in an LED tube lamp. Whenrectifying circuits 510 and 540 each comprise a half-wave rectifiercircuit described in FIGS. 30B-D, during a received AC signal's positiveor negative half cycle, the AC signal may receive from one of rectifyingcircuits 510 and 540, and later output from the other rectifying circuit510 or 540. Further, when rectifying circuits 510 and 540 each comprisethe rectifying circuit described in FIG. 30C or 30D, or when theycomprise the rectifying circuits in FIGS. 30C and 30D respectively,there may be only one terminal adapter circuit 541 for functions ofvoltage/current regulation or limiting, types of protection,current/voltage regulation, etc. within rectifying circuits 510 and 540,omitting another terminal adapter circuit 541 within rectifying circuit510 or 540.

FIG. 31A is a schematic diagram of the terminal adapter circuitaccording to an embodiment. Referring to FIG. 31A, terminal adaptercircuit 641 comprises a capacitor 642 having an end connected to pins501 and 502, and another end connected to half-wave node 819. Capacitor642 has an equivalent impedance to an AC signal, which impedanceincreases as the frequency of the AC signal decreases, and decreases asthe frequency increases. Therefore, capacitor 642 in terminal adaptercircuit 641 in this embodiment works as a high-pass filter. Further,terminal adapter circuit 641 is connected in series to an LED lightsource in the LED tube lamp, producing an equivalent impedance ofterminal adapter circuit 641 to perform a current/voltage limitingfunction on the LED light source, thereby preventing damaging of the LEDlight source by an excessive voltage across and/or current in the LEDlight source. In addition, choosing the value of capacitor 642 accordingto the frequency of the AC signal can further enhance voltage/currentregulation.

It's worth noting that terminal adapter circuit 641 may further includea capacitor 645 and/or capacitor 646. Capacitor 645 has an end connectedto half-wave node 819, and another end connected to pin 503. Capacitor646 has an end connected to half-wave node 819, and another endconnected to pin 504. For example, half-wave node 819 may be a commonconnective node between capacitors 645 and 646. And capacitor 642 actingas a current regulating capacitor is coupled to the common connectivenode and pins 501 and 502. In such a structure, serially connectedcapacitors 642 and 645 exist between one of pins 501 and 502 and pin503, and/or serially connected capacitors 642 and 646 exist between oneof pins 501 and 502 and pin 504. Through equivalent impedances ofserially connected capacitors, voltages from the AC signal are divided.Referring to FIGS. 29D and 31A, according to ratios between equivalentimpedances of the serially connected capacitors, the voltagesrespectively across capacitor 642 in rectifying circuit 510, filteringcircuit 520, and LED lighting module 530 can be controlled, making thecurrent flowing through an LED module in LED lighting module 530 beinglimited within a current rating, and then protecting/preventingfiltering circuit 520 and LED lighting module 530 from being damaged byexcessive voltages.

FIG. 31B is a schematic diagram of the terminal adapter circuitaccording to an embodiment. Referring to FIG. 31B, terminal adaptercircuit 741 comprises capacitors 743 and 744. Capacitor 743 has an endconnected to pin 501, and another end connected to half-wave node 819.Capacitor 744 has an end connected to pin 502, and another end connectedto half-wave node 819. Compared to terminal adapter circuit 641 in FIG.31A, terminal adapter circuit 741 has capacitors 743 and 744 in place ofcapacitor 642. Capacitance values of capacitors 743 and 744 may be thesame as each other, or may differ from each other depending on themagnitudes of signals to be received at pins 501 and 502.

Similarly, terminal adapter circuit 741 may further comprise a capacitor745 and/or a capacitor 746, respectively connected to pins 503 and 504.For example, each of pins 501 and 502 and each of pins 503 and 504 maybe connected in series to a capacitor, to achieve the functions ofvoltage division and other protections.

FIG. 31C is a schematic diagram of the terminal adapter circuitaccording to an embodiment. Referring to FIG. 31C, terminal adaptercircuit 841 comprises capacitors 842, 843, and 844. Capacitors 842 and843 are connected in series between pin 501 and half-wave node 819.Capacitors 842 and 844 are connected in series between pin 502 andhalf-wave node 819. In such a circuit structure, if any one ofcapacitors 842, 843, and 844 is shorted, there is still at least onecapacitor (of the other two capacitors) between pin 501 and half-wavenode 819 and between pin 502 and half-wave node 819, which performs acurrent-limiting function. Therefore, when a user accidentally gets anelectric shock, this circuit structure will prevent an excessive currentflowing through and then seriously hurting the body of the user.

Similarly, terminal adapter circuit 841 may further comprise a capacitor845 and/or a capacitor 846, respectively connected to pins 503 and 504.For example, each of pins 501 and 502 and each of pins 503 and 504 maybe connected in series to a capacitor, to achieve the functions ofvoltage division and other protections.

FIG. 31D is a schematic diagram of the terminal adapter circuitaccording to an embodiment. Referring to FIG. 31D, terminal adaptercircuit 941 comprises fuses 947 and 948. Fuse 947 has an end connectedto pin 501, and another end connected to half-wave node 819. Fuse 948has an end connected to pin 502, and another end connected to half-wavenode 819. With the fuses 947 and 948, when the current through each ofpins 501 and 502 exceeds a current rating of a corresponding connectedfuse 947 or 948, the corresponding fuse 947 or 948 will accordingly meltand then break the circuit to achieve overcurrent protection.

Each of the embodiments of the terminal adapter circuits as inrectifying circuits 510 and 810 coupled to pins 501 and 502 and shownand explained above can be used or included in the rectifying circuit540 shown in FIG. 29D, as when conductive pins 503 and 504 andconductive pins 501 and 502 are interchanged in position.

Capacitance values of the capacitors in the embodiments of the terminaladapter circuits shown and described above are in some embodiments inthe range, for example, of from 100 pF to 100 nF. Also, a capacitor usedin embodiments may be equivalently replaced by two or more capacitorsconnected in series or parallel. For example, each of capacitors 642 and842 may be replaced by two serially connected capacitors, one having acapacitance value chosen from the range, for example of from 1.0 nF to2.5 nF (such as, for example, about 1.5 nF), and the other having acapacitance value chosen from the range, for example of about 1.5 nF toabout 3.0 nF (such as, for example, about 2.2 nF).

FIG. 32A is a block diagram of the filtering circuit according to anembodiment. Rectifying circuit 510 is shown in FIG. 32A for illustratingits connection with other components, without intending filteringcircuit 520 to include rectifying circuit 510. Referring to FIG. 32A,filtering circuit 520 includes a filtering unit 523 coupled torectifying output terminals 511 and 512 to receive, and to filter outripples of, a rectified signal from rectifying circuit 510, therebyoutputting a filtered signal whose waveform is smoother than therectified signal. Filtering circuit 520 may further comprise anotherfiltering unit 524 coupled between a rectifying circuit and a pin, whichare for example rectifying circuit 510 and pin 501, rectifying circuit510 and pin 502, rectifying circuit 540 and pin 503, or rectifyingcircuit 540 and pin 504. Filtering unit 524 is configured to filter outa specific frequency component of an external driving signal. In thisembodiment of FIG. 32A, filtering unit 524 is coupled between rectifyingcircuit 510 and pin 501. Filtering circuit 520 may further compriseanother filtering unit 525 coupled between one of pins 501 and 502 and adiode of rectifying circuit 510, or between one of pins 503 and 504 anda diode of rectifying circuit 540, for reducing or filtering outelectromagnetic interference (EMI). In this embodiment, filtering unit525 is coupled between pin 501 and a diode (not shown in FIG. 32A) ofrectifying circuit 510. Since filtering units 524 and 525 may be presentor omitted depending on actual circumstances of their uses, they aredepicted by a dotted line in FIG. 32A.

FIG. 32B is a schematic diagram of the filtering unit according to anembodiment. Referring to FIG. 32B, the filtering unit 623 includes acapacitor 625 having an end coupled to output terminal 511 and afiltering output terminal 521 and another end coupled to output terminal512 and a filtering output terminal 522. The filtering unit 623 isconfigured to low-pass filter a rectified signal from output terminals511 and 512. Also, the filtering unit 623 filters out high-frequencycomponents of the rectified signal and thereby output a filtered signalat output terminals 521 and 522.

FIG. 32C is a schematic diagram of the filtering unit according to anembodiment. Referring to FIG. 32C, filtering unit 723 comprises a pifilter circuit including a capacitor 725, an inductor 726, and acapacitor 727. As is well known, a pi filter circuit looks like thesymbol n in its shape or structure. Capacitor 725 has an end connectedto output terminal 511 and coupled to output terminal 521 throughinductor 726, and has another end connected to output terminals 512 and522. Inductor 726 is coupled between output terminals 511 and 521.Capacitor 727 has an end connected to output terminal 521 and coupled tooutput terminal 511 through inductor 726, and has another end connectedto output terminals 512 and 522.

As seen between output terminals 511 and 512 and output terminals 521and 522, filtering unit 723 compared to filtering unit 623 in FIG. 32Badditionally has inductor 726 and capacitor 727, which are likecapacitor 725 in performing low-pass filtering. Therefore, filteringunit 723 in this embodiment compared to filtering unit 623 in FIG. 32Bhas a better ability to filter out high-frequency components to output afiltered signal with a smoother waveform.

Inductance values of inductor 726 in the embodiment described above arechosen in some embodiments in the range of about 10 nH to about 10 mH.And capacitance values of capacitors 625, 725, and 727 in theembodiments described above are chosen in some embodiments in the range,for example, of about 100 pF to about 1 uF.

FIG. 32D is a schematic diagram of the filtering unit according to anembodiment. Referring to FIG. 32D, filtering unit 824 includes acapacitor 825 and an inductor 828 connected in parallel. The capacitor825 has an end coupled to pin 501, and another end coupled to rectifyingoutput terminal 511. The capacitor 825 is configured to high-pass filteran external driving signal input at pin 501. Also, the capacitor 825filters out low-frequency components of the external driving signal. Theinductor 828 has an end coupled to pin 501 and another end coupled torectifying output terminal 511. The inductor 828 is configured tolow-pass filter an external driving signal input at pin 501. Also, theinductor 828 filters out high-frequency components of the externaldriving signal. Therefore, the combination of capacitor 825 and inductor828 works to present high impedance to an external driving signal at oneor more specific frequencies. In some embodiments, theparallel-connected capacitor and inductor work to present a peakequivalent impedance to the external driving signal at a specificfrequency.

Through appropriately choosing a capacitance value of capacitor 825 andan inductance value of inductor 828, a center frequency f on thehigh-impedance band may be set at a specific value given by

${f = \frac{1}{2\pi \overset{\_}{){LC}}}},$

where L denotes inductance of inductor 828 and C denotes capacitance ofcapacitor 825. The center frequency may be in the range of, for example,from 20 to 30 kHz. In some embodiments, the center frequency may beabout 25 kHz. An LED lamp with filtering unit 824 will be certifiedunder safety standards, for a specific center frequency, as provided byUnderwriters Laboratories (UL).

In an embodiment, the filtering unit 824 further comprises a resistor829, coupled between pin 501 and filtering output terminal 511. In FIG.32D, resistor 829 is connected in series to the parallel-connectedcapacitor 825 and inductor 828. For example, resistor 829 may be coupledbetween pin 501 and parallel-connected capacitor 825 and inductor 828,or may be coupled between filtering output terminal 511 andparallel-connected capacitor 825 and inductor 828. In this embodiment,resistor 829 is coupled between pin 501 and parallel-connected capacitor825 and inductor 828. Further, resistor 829 is configured for adjustingthe quality factor (Q) of the LC circuit comprising capacitor 825 andinductor 828, to better adapt filtering unit 824 to applicationenvironments with different quality factor requirements. Since resistor829 is an optional component, it is depicted in a dotted line in FIG.32D.

Capacitance values of capacitor 825 may be, for example, in the range ofabout 10 nF-2 uF. Inductance values of inductor 828 may be smaller than2 mH. In some embodiments, inductance values of inductor 828 may besmaller than 1 mH. Resistance values of resistor 829 may be larger than50 ohms. In some embodiments, resistance values of resistor 829 may belarger than 500 ohms.

Besides the filtering circuits shown and described in the aboveembodiments, traditional low-pass or band-pass filters can be used asthe filtering unit in the filtering circuit.

FIG. 32E is a schematic diagram of the filtering unit according to anembodiment. Referring to FIG. 32E, in this embodiment filtering unit 925is disposed in rectifying circuit 610 as shown in FIG. 30A, and isconfigured for reducing the EMI (Electromagnetic interference) caused byrectifying circuit 610 and/or other circuits. In this embodiment,filtering unit 925 includes an EMI-reducing capacitor coupled betweenpin 501 and the anode of rectifying diode 613, and between pin 502 andthe anode of rectifying diode 614, to reduce the EMI associated with thepositive half cycle of the AC driving signal received at pins 501 and502. The EMI-reducing capacitor of filtering unit 925 is also coupledbetween pin 501 and the cathode of rectifying diode 611, and between pin502 and the cathode of rectifying diode 612, to reduce the EMIassociated with the negative half cycle of the AC driving signalreceived at pins 501 and 502. In some embodiments, rectifying circuit610 comprises a full-wave bridge rectifier circuit including fourrectifying diodes 611, 612, 613, and 614. The full-wave bridge rectifiercircuit has a first filtering node connecting an anode and a cathoderespectively of two diodes 613 and 611 of the four rectifying diodes611, 612, 613, and 614, and a second filtering node connecting an anodeand a cathode respectively of the other two diodes 614 and 612 of thefour rectifying diodes 611, 612, 613, and 614. And the EMI-reducingcapacitor of the filtering unit 925 is coupled between the firstfiltering node and the second filtering node.

Similarly, with reference to FIGS. 30C, and 31A-31C, any capacitor ineach of the circuits in FIGS. 31A-31C is coupled between pins 501 and502 (or pins 503 and 504) and any diode in FIG. 30C, so any or eachcapacitor in FIGS. 31A-31C can work as an EMI-reducing capacitor toachieve the function of reducing EMI. For example, rectifying circuit510 in FIGS. 29B and 29D may comprise a half-wave rectifier circuitincluding two rectifying diodes and having a half-wave node connectingan anode and a cathode respectively of the two rectifying diodes, andany or each capacitor in FIGS. 31A-31C may be coupled between thehalf-wave node and at least one of the first pin and the second pin. Andrectifying circuit 540 in FIG. 29D may comprise a half-wave rectifiercircuit including two rectifying diodes and having a half-wave nodeconnecting an anode and a cathode respectively of the two rectifyingdiodes, and any or each capacitor in FIGS. 31A-31C may be coupledbetween the half-wave node and at least one of the third pin and thefourth pin.

It's worth noting that the EMI-reducing capacitor in the embodiment ofFIG. 32E may also act as capacitor 825 in filtering unit 824, so that incombination with inductor 828 the capacitor 825 performs the functionsof reducing EMI and presenting high impedance to an external drivingsignal at specific frequencies. For example, when the rectifying circuitcomprises a full-wave bridge rectifier circuit, capacitor 825 offiltering unit 824 may be coupled between the first filtering node andthe second filtering node of the full-wave bridge rectifier circuit.When the rectifying circuit comprises a half-wave rectifier circuit,capacitor 825 of filtering unit 824 may be coupled between the half-wavenode of the half-wave rectifier circuit and at least one of the firstpin and the second pin.

FIG. 33A is a schematic diagram of an LED module according to anembodiment. Referring to FIG. 33A, LED module 630 has an anode connectedto the filtering output terminal 521, has a cathode connected to thefiltering output terminal 522, and comprises at least one LED lightsource 632. When two or more LED light sources are included, they areconnected in parallel. The anode of each LED light source 632 isconnected to the anode of LED module 630 and thus output terminal 521,and the cathode of each LED light source 632 is connected to the cathodeof LED module 630 and thus output terminal 522. Each LED light source632 includes at least one LED 631. When multiple LEDs 631 are includedin an LED light source 632, they are connected in series, with the anodeof the first LED 631 connected to the anode of this LED light source632, and the cathode of the first LED 631 connected to the next orsecond LED 631. And the anode of the last LED 631 in this LED lightsource 632 is connected to the cathode of a previous LED 631, with thecathode of the last LED 631 connected to the cathode of this LED lightsource 632.

It's worth noting that LED module 630 may produce a current detectionsignal S531 reflecting a magnitude of current through LED module 630 andused for controlling or detecting on the LED module 630.

FIG. 33B is a schematic diagram of an LED module according to anembodiment. Referring to FIG. 33B, LED module 630 has an anode connectedto the filtering output terminal 521, has a cathode connected to thefiltering output terminal 522, and comprises at least two LED lightsources 732, with the anode of each LED light source 732 connected tothe anode of LED module 630, and the cathode of each LED light source732 connected to the cathode of LED module 630. Each LED light source732 includes at least two LEDs 731 connected in the same way asdescribed in FIG. 33A. For example, the anode of the first LED 731 in anLED light source 732 is connected to the anode of this LED light source732, the cathode of the first LED 731 is connected to the anode of thenext or second LED 731, and the cathode of the last LED 731 is connectedto the cathode of this LED light source 732. Further, LED light sources732 in an LED module 630 are connected to each other in this embodiment.All of the n-th LEDs 731 respectively of the LED light sources 732 areconnected by every anode of every n-th LED 731 in the LED light sources732, and by every cathode of every n-th LED 731, where n is a positiveinteger. In this way, the LEDs in LED module 630 in this embodiment areconnected in the form of a mesh.

Compared to the embodiments of FIGS. 34A-34G, LED lighting module 530 ofthe above embodiments includes LED module 630, but doesn't include adriving circuit for the LED module 630.

Similarly, LED module 630 in this embodiment may produce a currentdetection signal S531 reflecting a magnitude of current through LEDmodule 630 and used for controlling or detecting on the LED module 630.

The number of LEDs 731 included in an LED light source 732 may be in therange of from 15 to 25. In some embodiments, the number of LEDs 731 maybe in the range of from 18 to 22.

FIG. 33C is a planar view of a circuit layout of the LED moduleaccording to an embodiment. Referring to FIG. 33C, in this embodimentLEDs 831 are connected in the same way as described in FIG. 33B, andthree LED light sources are assumed in LED module 630 and described asfollows for illustration. A positive conductive line 834 and a negativeconductive line 835 are to receive a driving signal, for supplying powerto the LEDs 831. For example, positive conductive line 834 may becoupled to the filtering output terminal 521 of the filtering circuit520 described above, and negative conductive line 835 coupled to thefiltering output terminal 522 of the filtering circuit 520, to receive afiltered signal. For the convenience of illustration, all three of then-th LEDs 831 respectively of the three LED light sources are grouped asan LED set 833 in FIG. 33C.

Positive conductive line 834 connects the three first LEDs 831respectively of the leftmost three LED light sources, at the anodes onthe left sides of the three first LEDs 831 as shown in the leftmost LEDset 833 of FIG. 33C. Negative conductive line 835 connects the threelast LEDs 831 respectively of the leftmost three LED light sources, atthe cathodes on the right sides of the three last LEDs 831 as shown inthe rightmost LED set 833 of FIG. 33C. And of the three LED lightsources, the cathodes of the three first LEDs 831, the anodes of thethree last LEDs 831, and the anodes and cathodes of all the remainingLEDs 831 are connected by conductive lines or parts 839.

For example, the anodes of the three LEDs 831 in the leftmost LED set833 may be connected by positive conductive line 834, and their cathodesmay be connected by a leftmost conductive part 839. The anodes of thethree LEDs 831 in the second leftmost LED set 833 are also connected bythe leftmost conductive part 839, whereas their cathodes are connectedby a second leftmost conductive part 839. Since the cathodes of thethree LEDs 831 in the leftmost LED set 833 and the anodes of the threeLEDs 831 in the second leftmost LED set 833 are connected by the sameleftmost conductive part 839, in each of the three LED light sources thecathode of the first LED 831 is connected to the anode of the next orsecond LED 831, with the remaining LEDs 831 also being connected in thesame way. Accordingly, all the LEDs 831 of the three LED light sourcesare connected to form the mesh as shown in FIG. 33B.

It's worth noting that in this embodiment the length 836 of a portion ofeach conductive part 839 that immediately connects to the anode of anLED 831 is smaller than the length 837 of another portion of eachconductive part 839 that immediately connects to the cathode of an LED831, making the area of the latter portion immediately connecting to thecathode larger than that of the former portion immediately connecting tothe anode. The length 837 may be smaller than a length 838 of a portionof each conductive part 839 that immediately connects the cathode of anLED 831 and the anode of the next LED 831, making the area of theportion of each conductive part 839 that immediately connects a cathodeand an anode larger than the area of any other portion of eachconductive part 839 that immediately connects to only a cathode or ananode of an LED 831. Due to the length differences and area differences,this layout structure improves heat dissipation of the LEDs 831.

In some embodiments, positive conductive line 834 includes a lengthwiseportion 834 a, and negative conductive line 835 includes a lengthwiseportion 835 a, which are conducive to making the LED module have apositive “+” connective portion and a negative “−” connective portion ateach of the two ends of the LED module, as shown in FIG. 33C. Such alayout structure allows for coupling any of other circuits of the powersupply module of the LED lamp, including e.g. filtering circuit 520 andrectifying circuits 510 and 540, to the LED module through the positiveconnective portion and/or the negative connective portion at each orboth ends of the LED lamp. In some embodiments, the layout structureincreases the flexibility in arranging actual circuits in the LED lamp.

FIG. 33D is a planar view of a circuit layout of the LED moduleaccording to another embodiment. Referring to FIG. 33D, in thisembodiment LEDs 931 are connected in the same way as described in FIG.33A, and three LED light sources each including 7 LEDs 931 are assumedin LED module 630 and described as follows for illustration. A positiveconductive line 934 and a negative conductive line 935 are to receive adriving signal, for supplying power to the LEDs 931. For example,positive conductive line 934 may be coupled to the filtering outputterminal 521 of the filtering circuit 520 described above, and negativeconductive line 935 coupled to the filtering output terminal 522 of thefiltering circuit 520, to receive a filtered signal. For the convenienceof illustration, all seven LEDs 931 of each of the three LED lightsources are grouped as an LED set 932 in FIG. 33D. For example, thereare three LED sets 932 corresponding to the three LED light sources.

Positive conductive line 934 connects to the anode on the left side ofthe first or leftmost LED 931 of each of the three LED sets 932.Negative conductive line 935 connects to the cathode on the right sideof the last or rightmost LED 931 of each of the three LED sets 932. Ineach LED set 932, of two consecutive LEDs 931 the LED 931 on the lefthas a cathode connected by a conductive part 939 to an anode of the LED931 on the right. By such a layout, the LEDs 931 of each LED set 932 areconnected in series.

It's also worth noting that a conductive part 939 may be used to connectan anode and a cathode respectively of two consecutive LEDs 931.Negative conductive line 935 connects to the cathode of the last orrightmost LED 931 of each of the three LED sets 932. Positive conductiveline 934 connects to the anode of the first or leftmost LED 931 of eachof the three LED sets 932. Therefore, as shown in FIG. 33D, the length(and thus area) of the conductive part 939 is larger than that of theportion of negative conductive line 935 immediately connecting to acathode, which length (and thus area) is then larger than that of theportion of positive conductive line 934 immediately connecting to ananode. For example, the length 938 of the conductive part 939 may belarger than the length 937 of the portion of negative conductive line935 immediately connecting to a cathode of an LED 931, which length 937is then larger than the length 936 of the portion of positive conductiveline 934 immediately connecting to an anode of an LED 931. Such a layoutstructure improves heat dissipation of the LEDs 931 in LED module 630.

Positive conductive line 934 may include a lengthwise portion 934 a, andnegative conductive line 935 may include a lengthwise portion 935 a,which are conducive to making the LED module have a positive “+”connective portion and a negative “−” connective portion at each of thetwo ends of the LED module, as shown in FIG. 33D. Such a layoutstructure allows for coupling any of other circuits of the power supplymodule of the LED lamp, including e.g. filtering circuit 520 andrectifying circuits 510 and 540, to the LED module through the positiveconnective portion 934 a and/or the negative connective portion 935 a ateach or both ends of the LED lamp. In some embodiments, the layoutstructure increases the flexibility in arranging actual circuits in theLED lamp.

Further, the circuit layouts as shown in FIGS. 33C and 33D may beimplemented with a bendable circuit sheet or substrate, which may evenbe called flexible circuit board depending on its specific definitionused. For example, the bendable circuit sheet comprises one conductivelayer where positive conductive line 834, positive lengthwise portion834 a, negative conductive line 835, negative lengthwise portion 835 a,and conductive parts 839 shown in FIG. 33C, and positive conductive line934, positive lengthwise portion 934 a, negative conductive line 935,negative lengthwise portion 935 a, and conductive parts 939 shown inFIG. 33D are formed by the method of etching.

FIG. 33E is a planar view of a circuit layout of the LED moduleaccording to another embodiment. The layout structures of the LED modulein FIGS. 33E and 33C each correspond to the same way of connecting LEDs831 as that shown in FIG. 33B, but the layout structure in FIG. 33Ecomprises two conductive layers, instead of only one conductive layerfor forming the circuit layout as shown in FIG. 33C. Referring to FIG.33E, the main difference from the layout in FIG. 33C is that positiveconductive line 834 and negative conductive line 835 have a lengthwiseportion 834 a and a lengthwise portion 835 a, respectively, that areformed in a second conductive layer instead. The difference iselaborated as follows.

Referring to FIG. 33E, the bendable circuit sheet of the LED modulecomprises a first conductive layer 2 a and a second conductive layer 2 celectrically insulated from each other by a dielectric layer 2 b (notshown). Of the two conductive layers, positive conductive line 834,negative conductive line 835, and conductive parts 839 in FIG. 33E areformed in first conductive layer 2 a by the method of etching forelectrically connecting the plurality of LED components 831 e.g. in aform of a mesh, whereas positive lengthwise portion 834 a and negativelengthwise portion 835 a are formed in second conductive layer 2 c byetching for electrically connecting to (the filtering output terminalof) the filtering circuit. Further, positive conductive line 834 andnegative conductive line 835 in first conductive layer 2 a have viapoints 834 b and via points 835 b, respectively, for connecting tosecond conductive layer 2 c. Positive lengthwise portion 834 a andnegative lengthwise portion 835 a in second conductive layer 2 c havevia points 834 c and via points 835 c, respectively. Via points 834 bare positioned corresponding to via points 834 c, for connectingpositive conductive line 834 and positive lengthwise portion 834 a. Viapoints 835 b are positioned corresponding to via points 835 c, forconnecting negative conductive line 835 and negative lengthwise portion835 a. In some embodiments, the two conductive layers may be connectedby forming a hole connecting each via point 834 b and a correspondingvia point 834 c, and to form a hole connecting each via point 835 b anda corresponding via point 835 c, with the holes extending through thetwo conductive layers and the dielectric layer in-between. Positiveconductive line 834 and positive lengthwise portion 834 a can beelectrically connected by welding metallic part(s) through theconnecting hole(s), and negative conductive line 835 and negativelengthwise portion 835 a can be electrically connected by weldingmetallic part(s) through the connecting hole(s).

Similarly, the layout structure of the LED module in FIG. 33D mayalternatively have positive lengthwise portion 934 a and negativelengthwise portion 935 a disposed in a second conductive layer, toconstitute a two-layer layout structure.

It's worth noting that the thickness of the second conductive layer of atwo-layer bendable circuit sheet is in some embodiments larger than thatof the first conductive layer, in order to reduce the voltage drop orloss along each of the positive lengthwise portion and the negativelengthwise portion disposed in the second conductive layer. Compared toa one-layer bendable circuit sheet, since a positive lengthwise portionand a negative lengthwise portion are disposed in a second conductivelayer in a two-layer bendable circuit sheet, the width (between twolengthwise sides) of the two-layer bendable circuit sheet is or can bereduced. On the same fixture or plate in a production process, thenumber of bendable circuit sheets each with a shorter width that can belaid together at most is larger than the number of bendable circuitsheets each with a longer width that can be laid together at most. Insome embodiments, adopting a bendable circuit sheet with a smaller widthcan increase the efficiency of production of the LED module. Andreliability in the production process, such as the accuracy of weldingposition when welding (materials on) the LED components, can also beimproved, because a two-layer bendable circuit sheet can better maintainits shape.

As a variant of the above embodiments, a type of LED tube lamp isprovided which has at least some of the electronic components of itspower supply module disposed on a light strip of the LED tube lamp. Forexample, the technique of printed electronic circuit (PEC) can be usedto print, insert, or embed at least some of the electronic componentsonto the light strip.

In one embodiment, all electronic components of the power supply moduleare disposed on the light strip. The production process may include orproceed with the following steps: preparation of the circuit substrate(e.g. preparation of a flexible printed circuit board); ink jet printingof metallic nano-ink; ink jet printing of active and passive components(as of the power supply module); drying/sintering; ink jet printing ofinterlayer bumps; spraying of insulating ink; ink jet printing ofmetallic nano-ink; ink jet printing of active and passive components (tosequentially form the included layers); spraying of surface bond pad(s);and spraying of solder resist against LED components.

In certain embodiments, if all electronic components of the power supplymodule are disposed on the light strip, electrical connection betweenterminal pins of the LED tube lamp and the light strip may be achievedby connecting the pins to conductive lines which are welded with ends ofthe light strip. In this case, another substrate for supporting thepower supply module is not required, thereby allowing of an improveddesign or arrangement in the end cap(s) of the LED tube lamp. In someembodiments, components of the power supply module are disposed towardthe ends of the light strip, in order to significantly reduce the impactof heat generated from the power supply module's operations on the LEDcomponents. Since no substrate other than the light strip is used tosupport the power supply module in this case, the total amount ofwelding or soldering can be significantly reduced, improving the generalreliability of the power supply module.

Another case is that some of electronic components of the power supplymodule, such as some resistors and/or smaller size capacitors, areprinted onto the light strip, and some components with bigger size, suchas some inductors and/or electrolytic capacitors, are disposed in theend cap. The production process of the light strip in this case may bethe same as that described above. And in this case disposing some of allelectronic components on the light strip is conducive to achieving areasonable layout of the power supply module in the LED tube lamp, whichmay allow of an improved design in the end cap(s).

As a variant embodiment of the above, electronic components of the powersupply module are disposed on the light strip by a method of embeddingor inserting, e.g. by embedding the components onto a bendable orflexible light strip. In some embodiments, embedding is realized by amethod using copper-clad laminates (CCL) for forming a resistor orcapacitor; a method using ink related to silkscreen printing; or amethod of ink jet printing to embed passive components, wherein an inkjet printer is used to directly print inks to constitute passivecomponents and related functionalities to intended positions on thelight strip. Then through treatment by ultraviolet (UV) light ordrying/sintering, the light strip is formed where passive components areembedded. The electronic components embedded onto the light stripinclude for example resistors, capacitors, and inductors. In otherembodiments, active components also may be embedded. Through embeddingsome components onto the light strip, a reasonable layout of the powersupply module can be achieved to allow of an improved design in the endcap(s), because the surface area on a printed circuit board used forcarrying components of the power supply module is reduced or smaller.Thus, the size, weight, and thickness of the resulting printed circuitboard for carrying components of the power supply module is also smalleror reduced. Also in this situation since welding points on the printedcircuit board for welding resistors and/or capacitors if they were notto be disposed on the light strip are no longer used, the reliability ofthe power supply module is improved because these welding points aremost liable to (cause or incur) faults, malfunctions, or failures.Further, the length of conductive lines used for connecting componentson the printed circuit board is therefore also reduced, which allows ofa more compact layout of components on the printed circuit board andthus improving the functionalities of these components.

Next, methods to produce embedded capacitors and resistors are explainedas follows.

Usually, methods for manufacturing embedded capacitors employ or involvea concept called distributed or planar capacitance. The manufacturingprocess may include the following step(s). On a substrate of a copperlayer a thin insulation layer is applied or pressed, which is thengenerally disposed between a pair of layers including a power conductivelayer and a ground layer. The thin insulation layer makes the distancebetween the power conductive layer and the ground layer very short. Acapacitance resulting from this structure can also be realized by aconventional technique of a plated-through hole. Basically, this step isused to create this structure comprising a big parallel-plate capacitoron a circuit substrate.

For products of high electrical capacity, certain types of productsemploy distributed capacitances, and other types of products employseparate embedded capacitances. Through putting or adding a highdielectric-constant material such as barium titanate into the insulationlayer, the high electrical capacity is achieved.

A usual method for manufacturing embedded resistors employ conductive orresistive adhesive. This includes, for example, a resin to whichconductive carbon or graphite is added, which may be used as an additiveor filler. The additive resin is silkscreen printed to an objectlocation, and is then after treatment laminated inside the circuitboard. The resulting resistor is connected to other electroniccomponents through plated-through holes or microvias. Another method iscalled Ohmega-Ply, by which a metallic two-layered structure of a copperlayer and a thin nickel alloy layer constitutes a layer resistorrelative to a substrate. Then through etching the copper layer andnickel alloy layer, different types of nickel alloy resistors withcopper terminals can be formed. These types of resistor are eachlaminated inside the circuit board.

In an embodiment, conductive wires/lines are directly printed in alinear layout on an inner surface of the LED glass lamp tube, with LEDcomponents directly attached on the inner surface and electricallyconnected by the conductive wires. In some embodiments, the LEDcomponents in the form of chips are directly attached over theconductive wires on the inner surface, and connective points are atterminals of the wires for connecting the LED components and the powersupply module. After being attached, the LED chips may have fluorescentpowder applied or dropped thereon, for producing white light or light ofother color by the operating LED tube lamp.

Luminous efficacy of the LED or LED component may be 80 lm/W or above.In some embodiments, luminous efficiency of the LED or LED component maybe 120 lm/W or above. Certain optimal embodiments includes a luminousefficacy of the LED or LED component of 160 lm/W or above. White lightemitted by an LED component, such as those in the disclosed embodiments,may be produced by mixing fluorescent powder with the monochromaticlight emitted by a monochromatic LED chip. The white light in itsspectrum has major wavelength ranges of 430-460 nm and 550-560 nm, ormajor wavelength ranges of 430-460 nm, 540-560 nm, and 620-640 nm.

FIG. 34A is a block diagram of an LED lamp according to an embodiment.As shown in FIG. 34A, the power supply module of the LED lamp includesrectifying circuits 510 and 540, a filtering circuit 520, and a drivingcircuit 1530, and an LED lighting module 530 comprises the drivingcircuit 1530 and an LED module 630. LED lighting module 530 in thisembodiment comprises a driving circuit 1530 and an LED module 630.According to the above description in FIG. 29D, driving circuit 1530 inFIG. 34A comprises a DC-to-DC converter circuit, and is coupled tofiltering output terminals 521 and 522 to receive a filtered signal andthen perform power conversion for converting the filtered signal into adriving signal at driving output terminals 1521 and 1522. The LED module630 is coupled to driving output terminals 1521 and 1522 to receive thedriving signal for emitting light. In some embodiments, the current ofLED module 630 is stabilized at an objective current value. Descriptionsof this LED module 630 are the same as those provided above withreference to FIGS. 33A-33D.

It's worth noting that rectifying circuit 540 is an optional element andtherefore can be omitted, so it is depicted in a dotted line in FIG.34A. Accordingly, LED lighting module 530 in embodiments of FIGS. 34A,34C, and 34E may comprise a driving circuit 1530 and an LED module 630.Therefore, the power supply module of the LED lamp in this embodimentcan be used with a single-end power supply coupled to one end of the LEDlamp, and can be used with a dual-end power supply coupled to two endsof the LED lamp. With a single-end power supply, examples of the LEDlamp include an LED light bulb, a personal area light (PAL), etc.

FIG. 34B is a block diagram of the driving circuit according to anembodiment. Referring to FIG. 34B, the driving circuit includes acontroller 1531, and a conversion circuit 1532 for power conversionbased on a current source, for driving the LED module to emit light.Conversion circuit 1532 includes a switching circuit 1535 and an energystorage circuit 1538. And conversion circuit 1532 is coupled tofiltering output terminals 521 and 522 to receive and then convert afiltered signal, under the control by controller 1531, into a drivingsignal at driving output terminals 1521 and 1522 for driving the LEDmodule. Under the control by controller 1531, the driving signal outputby conversion circuit 1532 comprises a steady current, making the LEDmodule emitting steady light.

FIG. 34C is a schematic diagram of the driving circuit according to anembodiment. Referring to FIG. 34C, a driving circuit 1630 in thisembodiment comprises a buck DC-to-DC converter circuit having acontroller 1631 and a converter circuit. The converter circuit includesan inductor 1632, a diode 1633 for “freewheeling” of current, acapacitor 1634, and a switch 1635. Driving circuit 1630 is coupled tofiltering output terminals 521 and 522 to receive and then convert afiltered signal into a driving signal for driving an LED moduleconnected between driving output terminals 1521 and 1522.

In this embodiment, switch 1635 comprises a metal-oxide-semiconductorfield-effect transistor (MOSFET) and has a first terminal coupled to theanode of freewheeling diode 1633, a second terminal coupled to filteringoutput terminal 522, and a control terminal coupled to controller 1631used for controlling current conduction or cutoff between the first andsecond terminals of switch 1635. Driving output terminal 1521 isconnected to filtering output terminal 521, and driving output terminal1522 is connected to an end of inductor 1632, which has another endconnected to the first terminal of switch 1635. Capacitor 1634 iscoupled between driving output terminals 1521 and 1522, to stabilize thevoltage between driving output terminals 1521 and 1522. Freewheelingdiode 1633 has a cathode connected to driving output terminal 1521.

Next, a description follows as to an exemplary operation of drivingcircuit 1630.

Controller 1631 is configured for determining when to turn switch 1635on (in a conducting state) or off (in a cutoff state), according to acurrent detection signal S535 and/or a current detection signal S531.For example, in some embodiments, controller 1631 is configured tocontrol the duty cycle of switch 1635 being on and switch 1635 beingoff, in order to adjust the size or magnitude of the driving signal.Current detection signal S535 represents the magnitude of currentthrough switch 1635. Current detection signal S531 represents themagnitude of current through the LED module coupled between drivingoutput terminals 1521 and 1522. According to any of current detectionsignal S535 and current detection signal S531, controller 1631 canobtain information on the magnitude of power converted by the convertercircuit. When switch 1635 is switched on, a current of a filtered signalis input through filtering output terminal 521, and then flows throughcapacitor 1634, driving output terminal 1521, the LED module, inductor1632, and switch 1635, and then flows out from filtering output terminal522. During this flowing of current, capacitor 1634 and inductor 1632are performing storing of energy. On the other hand, when switch 1635 isswitched off, capacitor 1634 and inductor 1632 perform releasing ofstored energy by a current flowing from freewheeling capacitor 1633 todriving output terminal 1521 to make the LED module continuing to emitlight.

It's worth noting that capacitor 1634 is an optional element, so it canbe omitted and is thus depicted in a dotted line in FIG. 34C. In someapplication environments, the natural characteristic of an inductor tooppose instantaneous change in electric current passing through theinductor may be used to achieve the effect of stabilizing the currentthrough the LED module, thus omitting capacitor 1634.

FIG. 34D is a schematic diagram of the driving circuit according to anembodiment. Referring to FIG. 34D, a driving circuit 1730 in thisembodiment comprises a boost DC-to-DC converter circuit having acontroller 1731 and a converter circuit. The converter circuit includesan inductor 1732, a diode 1733 for “freewheeling” of current, acapacitor 1734, and a switch 1735. Driving circuit 1730 is configured toreceive and then convert a filtered signal from filtering outputterminals 521 and 522 into a driving signal for driving an LED modulecoupled between driving output terminals 1521 and 1522.

Inductor 1732 has an end connected to filtering output terminal 521, andanother end connected to the anode of freewheeling diode 1733 and afirst terminal of switch 1735, which has a second terminal connected tofiltering output terminal 522 and driving output terminal 1522.Freewheeling diode 1733 has a cathode connected to driving outputterminal 1521. And capacitor 1734 is coupled between driving outputterminals 1521 and 1522.

Controller 1731 is coupled to a control terminal of switch 1735, and isconfigured for determining when to turn switch 1735 on (in a conductingstate) or off (in a cutoff state), according to a current detectionsignal S535 and/or a current detection signal S531. When switch 1735 isswitched on, a current of a filtered signal is input through filteringoutput terminal 521, and then flows through inductor 1732 and switch1735, and then flows out from filtering output terminal 522. During thisflowing of current, the current through inductor 1732 increases withtime, with inductor 1732 being in a state of storing energy, whilecapacitor 1734 enters a state of releasing energy, making the LED modulecontinuing to emit light. On the other hand, when switch 1735 isswitched off, inductor 1732 enters a state of releasing energy as thecurrent through inductor 1732 decreases with time. In this state, thecurrent through inductor 1732 then flows through freewheeling diode1733, capacitor 1734, and the LED module, while capacitor 1734 enters astate of storing energy.

It's worth noting that capacitor 1734 is an optional element, so it canbe omitted, as is depicted by the dotted line in FIG. 34D. Whencapacitor 1734 is omitted and switch 1735 is switched on, the current ofinductor 1732 does not flow through the LED module, making the LEDmodule not emit light; but when switch 1735 is switched off, the currentof inductor 1732 flows through freewheeling diode 1733 to reach the LEDmodule, making the LED module emit light. Therefore, by controlling thetime that the LED module emits light, and the magnitude of currentthrough the LED module, the average luminance of the LED module can bestabilized to be above a defined value, thus also achieving the effectof emitting a steady light.

FIG. 34E is a schematic diagram of the driving circuit according to anembodiment. Referring to FIG. 34E, a driving circuit 1830 in thisembodiment comprises a buck DC-to-DC converter circuit having acontroller 1831 and a converter circuit. The converter circuit includesan inductor 1832, a diode 1833 for “freewheeling” of current, acapacitor 1834, and a switch 1835. Driving circuit 1830 is coupled tofiltering output terminals 521 and 522 to receive and then convert afiltered signal into a driving signal for driving an LED moduleconnected between driving output terminals 1521 and 1522.

Switch 1835 has a first terminal coupled to filtering output terminal521, a second terminal coupled to the cathode of freewheeling diode1833, and a control terminal coupled to controller 1831 to receive acontrol signal from controller 1831 for controlling current conductionor cutoff between the first and second terminals of switch 1835. Theanode of freewheeling diode 1833 is connected to filtering outputterminal 522 and driving output terminal 1522. Inductor 1832 has an endconnected to the second terminal of switch 1835, and another endconnected to driving output terminal 1521. Capacitor 1834 is coupledbetween driving output terminals 1521 and 1522, to stabilize the voltagebetween driving output terminals 1521 and 1522.

Controller 1831 is configured for controlling when to turn switch 1835on (in a conducting state) or off (in a cutoff state), according to acurrent detection signal S535 and/or a current detection signal S531.When switch 1835 is switched on, a current of a filtered signal is inputthrough filtering output terminal 521, and then flows through switch1835, inductor 1832, and driving output terminals 1521 and 1522, andthen flows out from filtering output terminal 522. During this flowingof current, the current through inductor 1832 and the voltage ofcapacitor 1834 both increase with time, so inductor 1832 and capacitor1834 are in a state of storing energy. On the other hand, when switch1835 is switched off, inductor 1832 is in a state of releasing energyand thus the current through it decreases with time. In this case, thecurrent through inductor 1832 circulates through driving outputterminals 1521 and 1522, freewheeling diode 1833, and back to inductor1832.

It's worth noting that capacitor 1834 is an optional element, so it canbe omitted and is thus depicted in a dotted line in FIG. 34E. Whencapacitor 1834 is omitted, no matter whether switch 1835 is turned on oroff, the current through inductor 1832 will flow through driving outputterminals 1521 and 1522 to drive the LED module to continue emittinglight.

FIG. 34F is a schematic diagram of the driving circuit according to anembodiment. Referring to FIG. 34F, a driving circuit 1930 in thisembodiment comprises a buck DC-to-DC converter circuit having acontroller 1931 and a converter circuit. The converter circuit includesan inductor 1932, a diode 1933 for “freewheeling” of current, acapacitor 1934, and a switch 1935. Driving circuit 1930 is coupled tofiltering output terminals 521 and 522 to receive and then convert afiltered signal into a driving signal for driving an LED moduleconnected between driving output terminals 1521 and 1522.

Inductor 1932 has an end connected to filtering output terminal 521 anddriving output terminal 1522, and another end connected to a first endof switch 1935. Switch 1935 has a second end connected to filteringoutput terminal 522, and a control terminal connected to controller 1931to receive a control signal from controller 1931 for controlling currentconduction or cutoff of switch 1935. Freewheeling diode 1933 has ananode coupled to a node connecting inductor 1932 and switch 1935, and acathode coupled to driving output terminal 1521. Capacitor 1934 iscoupled to driving output terminals 1521 and 1522, to stabilize thedriving of the LED module coupled between driving output terminals 1521and 1522.

Controller 1931 is configured for controlling when to turn switch 1935on (in a conducting state) or off (in a cutoff state), according to acurrent detection signal S531 and/or a current detection signal S535.When switch 1935 is turned on, a current is input through filteringoutput terminal 521, and then flows through inductor 1932 and switch1935, and then flows out from filtering output terminal 522. During thisflowing of current, the current through inductor 1932 increases withtime, so inductor 1932 is in a state of storing energy; but the voltageof capacitor 1934 decreases with time, so capacitor 1934 is in a stateof releasing energy to keep the LED module continuing to emit light. Onthe other hand, when switch 1935 is turned off, inductor 1932 is in astate of releasing energy and its current decreases with time. In thiscase, the current through inductor 1932 circulates through freewheelingdiode 1933, driving output terminals 1521 and 1522, and back to inductor1932. During this circulation, capacitor 1934 is in a state of storingenergy and its voltage increases with time.

It's worth noting that capacitor 1934 is an optional element, so it canbe omitted, as is depicted by the dotted line in FIG. 34F. Whencapacitor 1934 is omitted and switch 1935 is turned on, the currentthrough inductor 1932 doesn't flow through driving output terminals 1521and 1522, thereby making the LED module not emit light. On the otherhand, when switch 1935 is turned off, the current through inductor 1932flows through freewheeling diode 1933 and then the LED module to makethe LED module emit light. Therefore, by controlling the time that theLED module emits light, and the magnitude of current through the LEDmodule, the average luminance of the LED module can be stabilized to beabove a defined value, achieving the effect of emitting a steady light.

FIG. 34G is a block diagram of the driving circuit according to anembodiment. Referring to FIG. 34G, the driving circuit includes acontroller 2631, and a conversion circuit 2632 for power conversionbased on an adjustable current source, for driving the LED module toemit light. Conversion circuit 2632 includes a switching circuit 2635and an energy storage circuit 2638. And conversion circuit 2632 iscoupled to filtering output terminals 521 and 522 to receive and thenconvert a filtered signal, under the control by controller 2631, into adriving signal at driving output terminals 1521 and 1522 for driving theLED module. Controller 2631 is configured to receive a current detectionsignal S535 and/or a current detection signal S539, for controlling orstabilizing the driving signal output by conversion circuit 2632 to beabove an objective current value. Current detection signal S535represents the magnitude of current through switching circuit 2635.Current detection signal S539 represents the magnitude of currentthrough energy storage circuit 2638, which current may be e.g. aninductor current in energy storage circuit 2638 or a current output atdriving output terminal 1521. Any of current detection signal S535 andcurrent detection signal S539 can represent the magnitude of currentTout provided by the driving circuit from driving output terminals 1521and 1522 to the LED module. Controller 2631 is coupled to filteringoutput terminal 521 for setting the objective current value according tothe voltage Vin at filtering output terminal 521. Therefore, the currentTout provided by the driving circuit or the objective current value canbe adjusted corresponding to the magnitude of the voltage Vin of afiltered signal output by a filtering circuit.

It's worth noting that current detection signals S535 and S539 can begenerated by measuring current through a resistor or induced by aninductor. For example, a current can be measured according to a voltagedrop across a resistor in conversion circuit 2632 the current flowsthrough, or which arises from a mutual induction between an inductor inconversion circuit 2632 and another inductor in its energy storagecircuit 2638.

The above driving circuit structures are especially suitable for anapplication environment in which the external driving circuit for theLED tube lamp includes electronic ballast. An electronic ballast isequivalent to a current source whose output power is not constant. In aninternal driving circuit as shown in each of FIGS. 34C-34F, powerconsumed by the internal driving circuit relates to or depends on thenumber of LEDs in the LED module, and could be regarded as constant.When the output power of the electronic ballast is higher than powerconsumed by the LED module driven by the driving circuit, the outputvoltage of the ballast will increase continually, causing the level ofan AC driving signal received by the power supply module of the LED lampto continually increase, potentially damaging the ballast and/orcomponents of the power supply module due to their voltage ratings beingexceeded. On the other hand, when the output power of the electronicballast is lower than power consumed by the LED module driven by thedriving circuit, the output voltage of the ballast and the level of theAC driving signal will decrease continually so that the LED tube lampfail to normally operate.

The power needed for an LED lamp to work is already lower than thatneeded for a fluorescent lamp to work. If a conventional controlmechanism of e.g. using a backlight module to control the LED luminanceis used with a conventional driving system of e.g. a ballast, a problemwill probably arise of mismatch or incompatibility between the outputpower of the external driving system and the power needed by the LEDlamp. This problem may even cause damaging of the driving system and/orthe LED lamp. To prevent this problem, using e.g. the power/currentadjustment method described above in FIG. 34G enables the LED (tube)lamp to be better compatible with traditional fluorescent lightingsystem.

FIG. 34H is a graph illustrating the relationship between the voltageVin and the objective current value Tout according to an embodiment. InFIG. 34H, the variable Vin is on the horizontal axis, and the variableTout is on the vertical axis. In some cases, when the level of thevoltage Vin of a filtered signal is between the upper voltage limit VHand the lower voltage limit VL, the objective current value Tout will beabout an initial objective current value. The upper voltage limit VH ishigher than the lower voltage limit VL. When the voltage Vin increasesto be higher than the upper voltage limit VH, the objective currentvalue Tout will increase with the increasing of the voltage Vin. Duringthis stage, in certain embodiments, the slope of the relationship curveincreases with the increasing of the voltage Vin. When the voltage Vinof a filtered signal decreases to be below the lower voltage limit VL,the objective current value Tout will decrease with the decreasing ofthe voltage Vin. During this stage, in certain embodiments, the slope ofthe relationship curve decreases with the decreasing of the voltage Vin.For example, during the stage when the voltage Vin is higher than theupper voltage limit VH or lower than the lower voltage limit VL, theobjective current value Tout is in some embodiments a function of thevoltage Vin to the power of 2 or above, in order to make the rate ofincrease/decrease of the consumed power higher than the rate ofincrease/decrease of the output power of the external driving system. Insome embodiments, adjustment of the objective current value Tout is afunction of the filtered voltage Vin to the power of 2 or above.

In another case, when the voltage Vin of a filtered signal is betweenthe upper voltage limit VH and the lower voltage limit VL, the objectivecurrent value Tout of the LED lamp will vary, increase or decrease,linearly with the voltage Vin. During this stage, when the voltage Vinis at the upper voltage limit VH, the objective current value Tout willbe at the upper current limit IH. When the voltage Vin is at the lowervoltage limit VL, the objective current value Tout will be at the lowercurrent limit IL. The upper current limit IH is larger than the lowercurrent limit IL. And when the voltage Vin is between the upper voltagelimit VH and the lower voltage limit VL, the objective current valueTout will be a function of the voltage Vin to the power of 1.

With the designed relationship in FIG. 34H, when the output power of theballast is higher than the power consumed by the LED module driven bythe driving circuit, the voltage Vin will increase with time to exceedthe upper voltage limit VH. When the voltage Vin is higher than theupper voltage limit VH, the rate of increase of the consumed power ofthe LED module is higher than that of the output power of the electronicballast, and the output power and the consumed power will be balanced orequal when the voltage Vin is at a high balance voltage value VH+ andthe current Tout is at a high balance current value IH+. In this case,the high balance voltage value VH+ is larger than the upper voltagelimit VH, and the high balance current value IH+ is larger than theupper current limit IH. On the other hand, when the output power of theballast is lower than the power consumed by the LED module driven by thedriving circuit, the voltage Vin will decrease to be below the lowervoltage limit VL. When the voltage Vin is lower than the lower voltagelimit VL, the rate of decrease of the consumed power of the LED moduleis higher than that of the output power of the electronic ballast, andthe output power and the consumed power will be balanced or equal whenthe voltage Vin is at a low balance voltage value VL− and the objectivecurrent value Tout is at a low balance current value IL−. In this case,the low balance voltage value VL− is smaller than the lower voltagelimit VL, and the low balance current value IL− is smaller than thelower current limit IL.

In some embodiments, the lower voltage limit VL is defined to be around90% of the lowest output power of the electronic ballast, and the uppervoltage limit VH is defined to be around 110% of its highest outputpower. Taking a common AC powerline with a voltage range of 100-277volts and a frequency of 60 Hz as an example, the lower voltage limit VLmay be set at 90 volts (=100*90%), and the upper voltage limit VH may beset at 305 volts (=277*110%).

As to a short circuit board in at least one of the two end caps, it mayinclude a first short circuit substrate and a second short circuitsubstrate respectively connected to two terminal portions of a longcircuit sheet disposed in the lamp tube, and electronic components ofthe power supply module may be respectively disposed on the first shortcircuit substrate and the second short circuit substrate. The firstshort circuit substrate and the second short circuit substrate may haveroughly the same length, or different lengths. Each may also be referredto generally as a circuit board, and each may be a rigid circuit board.In general, a first short circuit substrate has a length that is about30%-80% of the length of a second short circuit substrate. In someembodiments, the length of the first short circuit substrate is about⅓˜⅔ of the length of the second short circuit substrate. For example, inone embodiment, the length of the first short circuit substrate may beabout half the length of the second short circuit substrate. The lengthof the second short circuit substrate may be, for example in the rangeof about 15 mm to about 65 mm, depending on actual applicationoccasions. In certain embodiments, the first short circuit substrate isdisposed in an end cap at an end of the LED tube lamp, and the secondshort circuit substrate is disposed in another end cap at the oppositeend of the LED tube lamp.

The short circuit board may have a length generally of about 15 mm toabout 40 mm, while the long circuit sheet may have a length generally ofabout 800 mm to about 2800 mm. In some embodiments, the short circuitboard may have a length of about 19 mm to about 36 mm, and the longcircuit sheet may have a length of about 1200 mm to about 2400 mm. Insome embodiments, a ratio of the length of the short circuit board tothe length of the long circuit sheet ranges from about 1:20 to about1:200.

For example, capacitors of the driving circuit, such as capacitors 1634,1734, 1834, and 1934 in FIGS. 34C-34F, in practical use may include twoor more capacitors connected in parallel. Some or all capacitors of thedriving circuit in the power supply module may be arranged on the firstshort circuit substrate of short circuit board, while other componentssuch as the rectifying circuit, filtering circuit, inductor(s) of thedriving circuit, controller(s), switch(es), diodes, etc. are arranged onthe second short circuit substrate of short circuit board. Sinceinductors, controllers, switches, etc. are electronic components withhigher temperature, arranging some or all capacitors on a circuitsubstrate separate or away from the circuit substrate(s) ofhigh-temperature components helps prevent the working life of capacitors(especially electrolytic capacitors) from being negatively affected bythe high-temperature components, thereby improving the reliability ofthe capacitors. Further, the physical separation between the capacitorsand both the rectifying circuit and filtering circuit also contributesto reducing the problem of EMI.

In some embodiments, the driving circuit has power conversion efficiencyof 80% or above. In some embodiments, the driving circuit may have apower conversion efficiency of 90% or above (such as, for example, 92%or above). Therefore, without the driving circuit, luminous efficacy ofthe LED lamp may be 120 lm/W or above. In some embodiments, without thedriving circuit, luminous efficacy of the LED lamp may be 160 lm/W orabove. On the other hand, with the driving circuit in combination withthe LED component(s), luminous efficacy of the LED lamp may be 120lm/W*90% (i.e., 108 lm/W) or above. In some embodiments, with thedriving circuit in combination with the LED component(s), luminousefficacy of the LED lamp may be 160 lm/W*92% (i.e., 147.2 lm/W) orabove.

Because the diffusion film or layer in an LED tube lamp has lighttransmittance of 85% or above, luminous efficacy of the LED tube lamp isin some embodiments 108 lm/W*85%=91.8 lm/W or above, and may be, in somemore effective embodiments, 147.2 lm/W*85%=125.12 lm/W.

FIG. 35A is a block diagram of an LED lamp according to an embodiment.Compared to FIG. 34A, the embodiment of FIG. 35A includes rectifyingcircuits 510 and 540, and a filtering circuit 520, and further includesan anti-flickering circuit 550; wherein the power supply module furtherincludes some components of an LED lighting module 530. Theanti-flickering circuit 550 is coupled between filtering circuit 520 andLED lighting module 530. It's noted that rectifying circuit 540 may beomitted, as is depicted by the dotted line in FIG. 35A.

Anti-flickering circuit 550 is coupled to filtering output terminals 521and 522, to receive a filtered signal, and under specific circumstancesto consume partial energy of the filtered signal for reducing (theincidence of) ripples of the filtered signal disrupting or interruptingthe light emission of the LED lighting module 530. In general, filteringcircuit 520 has such filtering components as resistor(s) and/orinductor(s), and/or parasitic capacitors and inductors, which may formresonant circuits. Upon breakoff or stop of an AC power signal, as whenthe power supply of the LED lamp is turned off by a user, theamplitude(s) of resonant signals in the resonant circuits will decreasewith time. But LEDs in the LED module of the LED lamp are unidirectionalconduction devices and require a minimum conduction voltage for the LEDmodule. When a resonant signal's trough value is lower than the minimumconduction voltage of the LED module, but its peak value is still higherthan the minimum conduction voltage, the flickering phenomenon willoccur in light emission of the LED module. In this case, anti-flickeringcircuit 550 works by allowing a current matching a defined flickeringcurrent value of the LED component to flow through, consuming partialenergy of the filtered signal higher than the energy difference of theresonant signal between its peak and trough values for reducing theflickering phenomenon. In certain embodiments, the anti-flickeringcircuit 550 is operable when the filtered signal's voltage approaches(and is still higher than) the minimum conduction voltage.

It's worth noting that anti-flickering circuit 550 may be more suitablefor the situation in which LED lighting module 530 doesn't includedriving circuit 1530, for example, when LED module 630 of LED lightingmodule 530 is (directly) driven to emit light by a filtered signal froma filtering circuit. In this case, the light emission of LED module 630will directly reflect variation in the filtered signal due to itsripples. In this situation, the introduction of anti-flickering circuit550 will prevent the flickering phenomenon from occurring in the LEDlamp upon the breakoff of power supply to the LED lamp.

FIG. 35B is a schematic diagram of the anti-flickering circuit accordingto an embodiment. Referring to FIG. 35B, anti-flickering circuit 650includes at least a resistor, such as two resistors connected in seriesbetween filtering output terminals 521 and 522. In this embodiment,anti-flickering circuit 650 is used for consuming partial energy of afiltered signal continually. When in normal operation of the LED lamp,this partial energy is far lower than the energy consumed by LEDlighting module 530. But upon an outage of the power supply, when thevoltage level of the filtered signal decreases to approach the minimumconduction voltage of LED module 630, this partial energy is stillconsumed by anti-flickering circuit 650 to offset the impact of theresonant signals which may cause the flickering of light emission of LEDmodule 630. In some embodiments, a current equal to or larger than ananti-flickering current level may be set to flow through anti-flickeringcircuit 650 when LED module 630 is supplied by the minimum conductionvoltage, and then an equivalent anti-flickering resistance ofanti-flickering circuit 650 can be determined based on the set current.

FIG. 36A is a block diagram of an LED lamp according to an embodiment.Compared to FIG. 35A, the embodiment of FIG. 36A includes rectifyingcircuits 510 and 540, a filtering circuit 520, an LED lighting module530, and an anti-flickering circuit 550, and further includes aprotection circuit 560; wherein the power supply module may also includesome components of an LED lighting module 530. Protection circuit 560 iscoupled to filtering output terminals 521 and 522, to detect thefiltered signal from filtering circuit 520 for determining whether toenter a protection state. Upon entering a protection state, protectioncircuit 560 works to limit, restrain, or clamp down on the level of thefiltered signal, preventing damaging of components in LED lightingmodule 530. And rectifying circuit 540 and anti-flickering circuit 550may be omitted, as depicted by the dotted line in FIG. 36A.

FIG. 36B is a schematic diagram of the protection circuit according toan embodiment. Referring to FIG. 36B, a protection circuit 660 includesa voltage clamping circuit, a voltage division circuit, capacitors 663and 670, resistor 669, and a diode 672, for entering a protection statewhen a current and/or voltage of the LED module is/are or might beexcessively high, thereby preventing damaging of the LED module. Thevoltage clamping circuit includes a bidirectional triode thyristor(TRIAC) 661 and a DIAC or symmetrical trigger diode 662. The voltagedivision circuit includes bipolar junction transistors (BJT) 667 and 668and resistors 664, 665, 666, and 671.

Bidirectional triode thyristor 661 has a first terminal connected tofiltering output terminal 521, a second terminal connected to filteringoutput terminal 522, and a control terminal connected to a firstterminal of symmetrical trigger diode 662, which has a second terminalconnected to an end of capacitor 663, which has another end connected tofiltering output terminal 522. Resistor 664 is in parallel to capacitor663, and has an end connected to the second terminal of symmetricaltrigger diode 662 and another end connected to filtering output terminal522. Resistor 665 has an end connected to the second terminal ofsymmetrical trigger diode 662 and another end connected to the collectorterminal of BJT 667, whose emitter terminal is connected to filteringoutput terminal 522. Resistor 666 has an end connected to the secondterminal of symmetrical trigger diode 662 and another end connected tothe collector terminal of BJT 668 and the base terminal of BJT 667. Theemitter terminal of BJT 668 is connected to filtering output terminal522. Resistor 669 has an end connected to the base terminal of BJT 668and another end connected to an end of capacitor 670, which has anotherend connected to filtering output terminal 522. Resistor 671 has an endconnected to the second terminal of symmetrical trigger diode 662 andanother end connected to the cathode of diode 672, whose anode isconnected to filtering output terminal 521.

It's worth noting that according to some embodiments, the resistance ofresistor 665 should be smaller than that of resistor 666.

Next, an exemplary operation of protection circuit 660 in overcurrentprotection is described as follows.

The node connecting resistor 669 and capacitor 670 is to receive acurrent detection signal S531, which represents the magnitude of currentthrough the LED module. The other end of resistor 671 is a voltageterminal 521′. In this embodiment concerning overcurrent protection,voltage terminal 521′ may be coupled to a biasing voltage source, or beconnected through diode 672 to filtering output terminal 521, as shownin FIG. 36B, to take a filtered signal as a biasing voltage source. Ifvoltage terminal 521′ is coupled to an external biasing voltage source,diode 672 may be omitted, so it is depicted in a dotted line in FIG.36B. The combination of resistor 669 and capacitor 670 can work tofilter out high frequency components of the current detection signalS531, and then input the filtered current detection signal S531 to thebase terminal of BJT 668 for controlling current conduction and cutoffof BJT 668. The filtering function of resistor 669 and capacitor 670 canprevent malfunction of BJT 668 due to noises. In practical use, resistor669 and capacitor 670 may be omitted, so they are each depicted in adotted line in FIG. 36B. When they are omitted, current detection signalS531 is input directly to the base terminal of BJT 668.

When the LED lamp is operating normally and the current of the LEDmodule is within a normal range, BJT 668 is in a cutoff state, andresistor 66 works to pull up the base voltage of BJT 667, whichtherefore enters a conducting state. In this state, the electricpotential at the second terminal of symmetrical trigger diode 662 isdetermined based on the voltage at voltage terminal 521′ of the biasingvoltage source and voltage division ratios between resistor 671 andparallel-connected resistors 664 and 665. Since the resistance ofresistor 665 is relatively small, voltage share for resistor 665 issmaller and the electric potential at the second terminal of symmetricaltrigger diode 662 is therefore pulled down. Then, the electric potentialat the control terminal of bidirectional triode thyristor 661 is in turnpulled down by symmetrical trigger diode 662, causing bidirectionaltriode thyristor 661 to enter a cutoff state, which cutoff state makesprotection circuit 660 not being in a protection state.

When the current of the LED module exceeds an overcurrent value, thelevel of current detection signal S531 will increase significantly tocause BJT 668 to enter a conducting state and then pull down the basevoltage of BJT 667, which thereby enters a cutoff state. In this case,the electric potential at the second terminal of symmetrical triggerdiode 662 is determined based on the voltage at voltage terminal 521′ ofthe biasing voltage source and voltage division ratios between resistor671 and parallel-connected resistors 664 and 666. Since the resistanceof resistor 666 is relatively high, voltage share for resistor 666 islarger and the electric potential at the second terminal of symmetricaltrigger diode 662 is therefore higher. Then the electric potential atthe control terminal of bidirectional triode thyristor 661 is in turnpulled up by symmetrical trigger diode 662, causing bidirectional triodethyristor 661 to enter a conducting state, which conducting state worksto restrain or clamp down on the voltage between filtering outputterminals 521 and 522 and thus makes protection circuit 660 being in aprotection state.

In this embodiment, the voltage at voltage terminal 521′ of the biasingvoltage source is determined based on the trigger voltage ofbidirectional triode thyristor 661, and voltage division ratio betweenresistor 671 and parallel-connected resistors 664 and 665, or voltagedivision ratio between resistor 671 and parallel-connected resistors 664and 666. Through voltage division between resistor 671 andparallel-connected resistors 664 and 665, the voltage from voltageterminal 521′ at symmetrical trigger diode 662 will be lower than thetrigger voltage of bidirectional triode thyristor 661. Otherwise,through voltage division between resistor 671 and parallel-connectedresistors 664 and 666, the voltage from voltage terminal 521′ atsymmetrical trigger diode 662 will be higher than the trigger voltage ofbidirectional triode thyristor 661. For example, in some embodiments,when the current of the LED module exceeds an overcurrent value, thevoltage division circuit is adjusted to the voltage division ratiobetween resistor 671 and parallel-connected resistors 664 and 666,causing a higher portion of the voltage at voltage terminal 521′ toresult at symmetrical trigger diode 662, achieving a hysteresisfunction. Specifically, BJTs 667 and 668 as switches are respectivelyconnected in series to resistors 665 and 666 which determine the voltagedivision ratios. The voltage division circuit is configured to controlturning on which one of BJTs 667 and 668 and leaving the other off fordetermining the relevant voltage division ratio, according to whetherthe current of the LED module exceeds an overcurrent value. And theclamping circuit determines whether to restrain or clamp down on thevoltage of the LED module according to the applying voltage divisionratio.

Next, an exemplary operation of protection circuit 660 in overvoltageprotection is described as follows.

The node connecting resistor 669 and capacitor 670 is to receive acurrent detection signal S531, which represents the magnitude of currentthrough the LED module. As described above, protection circuit 660 stillworks to provide overcurrent protection. The other end of resistor 671is a voltage terminal 521′. In this embodiment concerning overvoltageprotection, voltage terminal 521′ is coupled to the positive terminal ofthe LED module to detect the voltage of the LED module. Takingpreviously described embodiments for example, in embodiments of FIGS.33A and 33B, LED lighting module 530 doesn't include driving circuit1530, and the voltage terminal 521′ would be coupled to filtering outputterminal 521. Whereas in embodiments of FIGS. 34A-34G, LED lightingmodule 530 includes driving circuit 1530, and the voltage terminal 521′would be coupled to driving output terminal 1521. In this embodiment,voltage division ratios between resistor 671 and parallel-connectedresistors 664 and 665, and voltage division ratios between resistor 671and parallel-connected resistors 664 and 666 will be adjusted accordingto the voltage at voltage terminal 521′, for example, the voltage atdriving output terminal 1521 or filtering output terminal 521.Therefore, normal overcurrent protection can still be provided byprotection circuit 660.

In some embodiments, when the LED lamp is operating normally, assumingovercurrent condition doesn't occur, the electric potential at thesecond terminal of symmetrical trigger diode 662 is determined based onthe voltage at voltage terminal 521′ and voltage division ratios betweenresistor 671 and parallel-connected resistors 664 and 665, and isinsufficient to trigger bidirectional triode thyristor 661. Thenbidirectional triode thyristor 661 is in a cutoff state, makingprotection circuit 660 not being in a protection state. On the otherhand, when the LED module is operating abnormally with the voltage atthe positive terminal of the LED module exceeding an overvoltage value,the electric potential at the second terminal of symmetrical triggerdiode 662 is sufficiently high to trigger bidirectional triode thyristor661 when the voltage at the first terminal of symmetrical trigger diode662 is larger than the trigger voltage of bidirectional triode thyristor661. Then bidirectional triode thyristor 661 enters a conducting state,making protection circuit 660 being in a protection state to restrain orclamp down on the level of the filtered signal.

As described above, protection circuit 660 provides one or two of thefunctions of overcurrent protection and overvoltage protection.

In some embodiments, protection circuit 660 may further include a Zenerdiode connected to resistor 664 in parallel, which Zener diode is usedto limit or restrain the voltage across resistor 664. The breakdownvoltage of the Zener diode may be in the range of about 25˜50 volts. Insome embodiments, the breakdown voltage of the Zener diode may be about36 volts.

Further, a silicon controlled rectifier may be substituted forbidirectional triode thyristor 661, without negatively affecting theprotection functions. Using a silicon controlled rectifier instead of abidirectional triode thyristor 661 has a lower voltage drop acrossitself in conduction than that across bidirectional triode thyristor 661in conduction.

In one embodiment, values of the parameters of protection circuit 660may be set as follows. Resistance of resistor 669 may be about 10 ohms.Capacitance of capacitor 670 may be about 1 nF. Capacitance of capacitor633 may be about 10 nF. The (breakover) voltage of symmetrical triggerdiode 662 may be in the range of about 26˜36 volts. Resistance ofresistor 671 may be in the range of about 300 k˜600 k ohms. In someembodiments, resistance of resistor 671 may be about 540 k ohms.Resistance of resistor 666 may be in the range of about 100 k˜300 kohms. In some embodiments, resistance of resistor 666 may be about 220 kohms. Resistance of resistor 665 may be in the range of about 30 k˜100 kohms. In some embodiments, resistance of resistor 665 may be about 40 kohms. Resistance of resistor 664 is in some embodiments in the range ofabout 100 k 300 k ohms, and may preferably be, in some embodiments about220 k ohms.

FIG. 37A is a block diagram of an LED lamp according to an embodiment.Compared to FIG. 34A, the embodiment of FIG. 37A includes rectifyingcircuits 510 and 540, a filtering circuit 520, and a driving circuit1530, and further includes a mode switching circuit 580; wherein an LEDlighting module 530 is composed of driving circuit 1530 and an LEDmodule 630. Mode switching circuit 580 is coupled to at least one offiltering output terminals 521 and 522 and at least one of drivingoutput terminals 1521 and 1522, for determining whether to perform afirst driving mode or a second driving mode, as according to a frequencyof the external driving signal. In the first driving mode, a filteredsignal from filtering circuit 520 is input into driving circuit 1530,while in the second driving mode the filtered signal bypasses at least acomponent of driving circuit 1530, making driving circuit 1530 stopworking in conducting the filtered signal, allowing the filtered signalto (directly) reach and drive LED module 630. The bypassed component(s)of driving circuit 1530 may include an inductor or a switch, which whenbypassed makes driving circuit 1530 unable to transfer and/or convertpower, and then stop working in conducting the filtered signal. Ifdriving circuit 1530 includes a capacitor, the capacitor can still beused to filter out ripples of the filtered signal in order to stabilizethe voltage across the LED module. When mode switching circuit 580determines to perform the first driving mode, allowing the filteredsignal to be input to driving circuit 1530, driving circuit 1530 thentransforms the filtered signal into a driving signal for driving LEDmodule 630 to emit light. On the other hand, when mode switching circuit580 determines to perform the second driving mode, allowing the filteredsignal to bypass driving circuit 1530 to reach LED module 630, filteringcircuit 520 then becomes in effect a driving circuit for LED module 630.Then filtering circuit 520 provides the filtered signal as a drivingsignal for the LED module for driving the LED module to emit light.

It's worth noting that mode switching circuit 580 can determine whetherto perform the first driving mode or the second driving mode based on auser's instruction or a detected signal received by the LED lamp throughpins 501, 502, 503, and 504. With the mode switching circuit, the powersupply module of the LED lamp can adapt to or perform one of appropriatedriving modes corresponding to different application environments ordriving systems, thus improving the compatibility of the LED lamp. Insome embodiments, rectifying circuit 540 may be omitted, as is depictedby the dotted line in FIG. 37A.

FIG. 37B is a schematic diagram of the mode switching circuit in an LEDlamp according to an embodiment. Referring to FIG. 37B, a mode switchingcircuit 680 includes a mode switch 681 suitable for use with the drivingcircuit 1630 in FIG. 34C. Referring to FIGS. 37B and 34C, mode switch681 has three terminals 683, 684, and 685, wherein terminal 683 iscoupled to driving output terminal 1522, terminal 684 is coupled tofiltering output terminal 522, and terminal 685 is coupled to theinductor 1632 in driving circuit 1630.

When mode switching circuit 680 determines to perform a first drivingmode, mode switch 681 conducts current in a first conductive paththrough terminals 683 and 685 and a second conductive path throughterminals 683 and 684 is in a cutoff state. In this case, driving outputterminal 1522 is coupled to inductor 1632, and therefore driving circuit1630 is working normally, which working includes receiving a filteredsignal from filtering output terminals 521 and 522 and then transformingthe filtered signal into a driving signal, output at driving outputterminals 1521 and 1522 for driving the LED module.

When mode switching circuit 680 determines to perform a second drivingmode, mode switch 681 conducts current in the second conductive paththrough terminals 683 and 684 and the first conductive path throughterminals 683 and 685 is in a cutoff state. In this case, driving outputterminal 1522 is coupled to filtering output terminal 522, and thereforedriving circuit 1630 stops working, and a filtered signal is inputthrough filtering output terminals 521 and 522 to driving outputterminals 1521 and 1522 for driving the LED module, while bypassinginductor 1632 and switch 1635 in driving circuit 1630.

FIG. 37C is a schematic diagram of the mode switching circuit in an LEDlamp according to an embodiment. Referring to FIG. 37C, a mode switchingcircuit 780 includes a mode switch 781 suitable for use with the drivingcircuit 1630 in FIG. 34C. Referring to FIGS. 37C and 34C, mode switch781 has three terminals 783, 784, and 785, wherein terminal 783 iscoupled to filtering output terminal 522, terminal 784 is coupled todriving output terminal 1522, and terminal 785 is coupled to switch 1635in driving circuit 1630.

When mode switching circuit 780 determines to perform a first drivingmode, mode switch 781 conducts current in a first conductive paththrough terminals 783 and 785 and a second conductive path throughterminals 783 and 784 is in a cutoff state. In this case, filteringoutput terminal 522 is coupled to switch 1635, and therefore drivingcircuit 1630 is working normally, which working includes receiving afiltered signal from filtering output terminals 521 and 522 and thentransforming the filtered signal into a driving signal, output atdriving output terminals 1521 and 1522 for driving the LED module.

When mode switching circuit 780 determines to perform a second drivingmode, mode switch 781 conducts current in the second conductive paththrough terminals 783 and 784 and the first conductive path throughterminals 783 and 785 is in a cutoff state. In this case, driving outputterminal 1522 is coupled to filtering output terminal 522, and thereforedriving circuit 1630 stops working, and a filtered signal is inputthrough filtering output terminals 521 and 522 to driving outputterminals 1521 and 1522 for driving the LED module, while bypassinginductor 1632 and switch 1635 in driving circuit 1630.

FIG. 37D is a schematic diagram of the mode switching circuit in an LEDlamp according to an embodiment. Referring to FIG. 37D, a mode switchingcircuit 880 includes a mode switch 881 suitable for use with the drivingcircuit 1730 in FIG. 34D. Referring to FIGS. 37D and 34D, mode switch881 has three terminals 883, 884, and 885, wherein terminal 883 iscoupled to filtering output terminal 521, terminal 884 is coupled todriving output terminal 1521, and terminal 885 is coupled to inductor1732 in driving circuit 1730.

When mode switching circuit 880 determines to perform a first drivingmode, mode switch 881 conducts current in a first conductive paththrough terminals 883 and 885 and a second conductive path throughterminals 883 and 884 is in a cutoff state. In this case, filteringoutput terminal 521 is coupled to inductor 1732, and therefore drivingcircuit 1730 is working normally, which working includes receiving afiltered signal from filtering output terminals 521 and 522 and thentransforming the filtered signal into a driving signal, output atdriving output terminals 1521 and 1522 for driving the LED module.

When mode switching circuit 880 determines to perform a second drivingmode, mode switch 881 conducts current in the second conductive paththrough terminals 883 and 884 and the first conductive path throughterminals 883 and 885 is in a cutoff state. In this case, driving outputterminal 1521 is coupled to filtering output terminal 521, and thereforedriving circuit 1730 stops working, and a filtered signal is inputthrough filtering output terminals 521 and 522 to driving outputterminals 1521 and 1522 for driving the LED module, while bypassinginductor 1732 and freewheeling diode 1733 in driving circuit 1730.

FIG. 37E is a schematic diagram of the mode switching circuit in an LEDlamp according to an embodiment. Referring to FIG. 37E, a mode switchingcircuit 980 includes a mode switch 981 suitable for use with the drivingcircuit 1730 in FIG. 34D. Referring to FIGS. 37E and 34D, mode switch981 has three terminals 983, 984, and 985, wherein terminal 983 iscoupled to driving output terminal 1521, terminal 984 is coupled tofiltering output terminal 521, and terminal 985 is coupled to thecathode of diode 1733 in driving circuit 1730.

When mode switching circuit 980 determines to perform a first drivingmode, mode switch 981 conducts current in a first conductive paththrough terminals 983 and 985 and a second conductive path throughterminals 983 and 984 is in a cutoff state. In this case, filteringoutput terminal 521 is coupled to the cathode of diode 1733, andtherefore driving circuit 1730 is working normally, which workingincludes receiving a filtered signal from filtering output terminals 521and 522 and then transforming the filtered signal into a driving signal,output at driving output terminals 1521 and 1522 for driving the LEDmodule.

When mode switching circuit 980 determines to perform a second drivingmode, mode switch 981 conducts current in the second conductive paththrough terminals 983 and 984 and the first conductive path throughterminals 983 and 985 is in a cutoff state. In this case, driving outputterminal 1521 is coupled to filtering output terminal 521, and thereforedriving circuit 1730 stops working, and a filtered signal is inputthrough filtering output terminals 521 and 522 to driving outputterminals 1521 and 1522 for driving the LED module, while bypassinginductor 1732 and freewheeling diode 1733 in driving circuit 1730.

FIG. 37F is a schematic diagram of the mode switching circuit in an LEDlamp according to an embodiment. Referring to FIG. 37F, a mode switchingcircuit 1680 includes a mode switch 1681 suitable for use with thedriving circuit 1830 in FIG. 34E. Referring to FIGS. 37F and 34E, modeswitch 1681 has three terminals 1683, 1684, and 1685, wherein terminal1683 is coupled to filtering output terminal 521, terminal 1684 iscoupled to driving output terminal 1521, and terminal 1685 is coupled toswitch 1835 in driving circuit 1830.

When mode switching circuit 1680 determines to perform a first drivingmode, mode switch 1681 conducts current in a first conductive paththrough terminals 1683 and 1685 and a second conductive path throughterminals 1683 and 1684 is in a cutoff state. In this case, filteringoutput terminal 521 is coupled to switch 1835, and therefore drivingcircuit 1830 is working normally, which working includes receiving afiltered signal from filtering output terminals 521 and 522 and thentransforming the filtered signal into a driving signal, output atdriving output terminals 1521 and 1522 for driving the LED module.

When mode switching circuit 1680 determines to perform a second drivingmode, mode switch 1681 conducts current in the second conductive paththrough terminals 1683 and 1684 and the first conductive path throughterminals 1683 and 1685 is in a cutoff state. In this case, drivingoutput terminal 1521 is coupled to filtering output terminal 521, andtherefore driving circuit 1830 stops working, and a filtered signal isinput through filtering output terminals 521 and 522 to driving outputterminals 1521 and 1522 for driving the LED module, while bypassinginductor 1832 and switch 1835 in driving circuit 1830.

FIG. 37G is a schematic diagram of the mode switching circuit in an LEDlamp according to an embodiment. Referring to FIG. 37G, a mode switchingcircuit 1780 includes a mode switch 1781 suitable for use with thedriving circuit 1830 in FIG. 34E. Referring to FIGS. 37G and 34E, modeswitch 1781 has three terminals 1783, 1784, and 1785, wherein terminal1783 is coupled to filtering output terminal 521, terminal 1784 iscoupled to driving output terminal 1521, and terminal 1785 is coupled toinductor 1832 in driving circuit 1830.

When mode switching circuit 1780 determines to perform a first drivingmode, mode switch 1781 conducts current in a first conductive paththrough terminals 1783 and 1785 and a second conductive path throughterminals 1783 and 1784 is in a cutoff state. In this case, filteringoutput terminal 521 is coupled to inductor 1832, and therefore drivingcircuit 1830 is working normally, which working includes receiving afiltered signal from filtering output terminals 521 and 522 and thentransforming the filtered signal into a driving signal, output atdriving output terminals 1521 and 1522 for driving the LED module.

When mode switching circuit 1780 determines to perform a second drivingmode, mode switch 1781 conducts current in the second conductive paththrough terminals 1783 and 1784 and the first conductive path throughterminals 1783 and 1785 is in a cutoff state. In this case, drivingoutput terminal 1521 is coupled to filtering output terminal 521, andtherefore driving circuit 1830 stops working, and a filtered signal isinput through filtering output terminals 521 and 522 to driving outputterminals 1521 and 1522 for driving the LED module, while bypassinginductor 1832 and switch 1835 in driving circuit 1830.

FIG. 37H is a schematic diagram of the mode switching circuit in an LEDlamp according to an embodiment. Referring to FIG. 37H, a mode switchingcircuit 1880 includes mode switches 1881 and 1882 suitable for use withthe driving circuit 1930 in FIG. 34F. Referring to FIGS. 37H and 34F,mode switch 1881 has three terminals 1883, 1884, and 1885, whereinterminal 1883 is coupled to driving output terminal 1521, terminal 1884is coupled to filtering output terminal 521, and terminal 1885 iscoupled to freewheeling diode 1933 in driving circuit 1930. And modeswitch 1882 has three terminals 1886, 1887, and 1888, wherein terminal1886 is coupled to driving output terminal 1522, terminal 1887 iscoupled to filtering output terminal 522, and terminal 1888 is coupledto filtering output terminal 521.

When mode switching circuit 1880 determines to perform a first drivingmode, mode switch 1881 conducts current in a first conductive paththrough terminals 1883 and 1885 and a second conductive path throughterminals 1883 and 1884 is in a cutoff state, and mode switch 1882conducts current in a third conductive path through terminals 1886 and1888 and a fourth conductive path through terminals 1886 and 1887 is ina cutoff state. In this case, driving output terminal 1521 is coupled tofreewheeling diode 1933, and filtering output terminal 521 is coupled todriving output terminal 1522. Therefore, driving circuit 1930 is workingnormally, which working includes receiving a filtered signal fromfiltering output terminals 521 and 522 and then transforming thefiltered signal into a driving signal, output at driving outputterminals 1521 and 1522 for driving the LED module.

When mode switching circuit 1880 determines to perform a second drivingmode, mode switch 1881 conducts current in the second conductive paththrough terminals 1883 and 1884 and the first conductive path throughterminals 1883 and 1885 is in a cutoff state, and mode switch 1882conducts current in the fourth conductive path through terminals 1886and 1887 and the third conductive path through terminals 1886 and 1888is in a cutoff state. In this case, driving output terminal 1521 iscoupled to filtering output terminal 521, and filtering output terminal522 is coupled to driving output terminal 1522. Therefore, drivingcircuit 1930 stops working, and a filtered signal is input throughfiltering output terminals 521 and 522 to driving output terminals 1521and 1522 for driving the LED module, while bypassing freewheeling diode1933 and switch 1935 in driving circuit 1930.

FIG. 37I is a schematic diagram of the mode switching circuit in an LEDlamp according to an embodiment. Referring to FIG. 37I, a mode switchingcircuit 1980 includes mode switches 1981 and 1982 suitable for use withthe driving circuit 1930 in FIG. 34F. Referring to FIGS. 37I and 34F,mode switch 1981 has three terminals 1983, 1984, and 1985, whereinterminal 1983 is coupled to filtering output terminal 522, terminal 1984is coupled to driving output terminal 1522, and terminal 1985 is coupledto switch 1935 in driving circuit 1930. And mode switch 1982 has threeterminals 1986, 1987, and 1988, wherein terminal 1986 is coupled tofiltering output terminal 521, terminal 1987 is coupled to drivingoutput terminal 1521, and terminal 1988 is coupled to driving outputterminal 1522.

When mode switching circuit 1980 determines to perform a first drivingmode, mode switch 1981 conducts current in a first conductive paththrough terminals 1983 and 1985 and a second conductive path throughterminals 1983 and 1984 is in a cutoff state, and mode switch 1982conducts current in a third conductive path through terminals 1986 and1988 and a fourth conductive path through terminals 1986 and 1987 is ina cutoff state. In this case, driving output terminal 1522 is coupled tofiltering output terminal 521, and filtering output terminal 522 iscoupled to switch 1935. Therefore, driving circuit 1930 is workingnormally, which working includes receiving a filtered signal fromfiltering output terminals 521 and 522 and then transforming thefiltered signal into a driving signal, output at driving outputterminals 1521 and 1522 for driving the LED module.

When mode switching circuit 1980 determines to perform a second drivingmode, mode switch 1981 conducts current in the second conductive paththrough terminals 1983 and 1984 and the first conductive path throughterminals 1983 and 1985 is in a cutoff state, and mode switch 1982conducts current in the fourth conductive path through terminals 1986and 1987 and the third conductive path through terminals 1986 and 1988is in a cutoff state. In this case, driving output terminal 1521 iscoupled to filtering output terminal 521, and filtering output terminal522 is coupled to driving output terminal 1522. Therefore, drivingcircuit 1930 stops working, and a filtered signal is input throughfiltering output terminals 521 and 522 to driving output terminals 1521and 1522 for driving the LED module, while bypassing freewheeling diode1933 and switch 1935 in driving circuit 1930.

In an embodiment, each of the mode switches comprises, for example, asingle-pole double-throw switch, or comprises two semiconductor switches(such as metal oxide semiconductor transistors), for switching aconductive path on to conduct current while leaving the other conductivepath cutoff. Each of the two conductive paths provides a path forconducting the filtered signal, allowing the current of the filteredsignal to flow through one of the two paths, thereby achieving thefunction of mode switching or selection. For example, with reference toFIGS. 29A and 29C in addition, when the lamp driving circuit 505 is notpresent and the LED tube lamp 500 is directly supplied by the AC powersupply 508, the mode switching circuit may determine on performing afirst driving mode in which the driving circuit (such as driving circuit1530, 1630, 1730, 1830, or 1930) transforms the filtered signal into adriving signal of a level meeting a required level to properly drive theLED module to emit light. On the other hand, when the lamp drivingcircuit 505 is present, the mode switching circuit may determine onperforming a second driving mode in which the filtered signal is(almost) directly used to drive the LED module to emit light; oralternatively the mode switching circuit may determine on performing thefirst driving mode to drive the LED module to emit light.

FIG. 38A is a block diagram of an LED lamp according to an embodiment.Compared to FIG. 29D, the embodiment of FIG. 38A includes rectifyingcircuits 510 and 540, and a filtering circuit 520, and further includesa ballast-compatible circuit 1510; wherein the power supply module mayalso include some components of an LED lighting module 530. Theballast-compatible circuit 1510 may be coupled between pin 501 and/orpin 502 and rectifying circuit 510. This embodiment is explainedassuming the ballast-compatible circuit 1510 to be coupled between pin501 and rectifying circuit 510. With reference to FIGS. 29A and 29C inaddition to FIG. 38A, lamp driving circuit 505 comprises a ballastconfigured to provide an AC driving signal to drive the LED lamp in thisembodiment.

In an initial stage upon the activation of the driving system of lampdriving circuit 505, lamp driving circuit 505's ability to outputrelevant signal(s) has not risen to a standard state. However, in theinitial stage the power supply module of the LED lamp instantly orrapidly receives or conducts the AC driving signal provided by lampdriving circuit 505, which initial conduction is likely to fail thestarting of the LED lamp by lamp driving circuit 505 as lamp drivingcircuit 505 is initially loaded by the LED lamp in this stage. Forexample, internal components of lamp driving circuit 505 may retrievepower from a transformed output in lamp driving circuit 505, in order tomaintain their operation upon the activation. In this case, theactivation of lamp driving circuit 505 may end up failing as its outputvoltage could not normally rise to a required level in this initialstage; or the quality factor (Q) of a resonant circuit in lamp drivingcircuit 505 may vary as a result of the initial loading from the LEDlamp, so as to cause the failure of the activation.

In this embodiment, in the initial stage upon activation,ballast-compatible circuit 1510 will be in an open-circuit state,preventing the energy of the AC driving signal from reaching the LEDmodule. After a defined delay upon the AC driving signal as an externaldriving signal being input to the LED tube lamp, ballast-compatiblecircuit 1510 switches from a cutoff state during the delay to aconducting state, allowing the energy of the AC driving signal to startto reach the LED module. By means of the delayed conduction ofballast-compatible circuit 1510, operation of the LED lamp simulates thelamp-starting characteristics of a fluorescent lamp, that is, internalgases of the fluorescent lamp will normally discharge for light emissionafter a delay upon activation of a driving power supply. Therefore,ballast-compatible circuit 1510 further improves the compatibility ofthe LED lamp with lamp driving circuits 505 such as an electronicballast.

In this embodiment, rectifying circuit 540 may be omitted and istherefore depicted by a dotted line in FIG. 38A.

It's noted that in any embodiments using the ballast-compatible circuitdescribed with reference to FIGS. 38A˜I in this disclosure, upon theexternal driving signal being initially input at the first pin andsecond pin, the ballast-compatible circuit will not enter a conductionstate until a period of delay passes, wherein the period is typicallybetween about 10 ms (or millisecond) and 1 second. And in someembodiments, the period may be between about 10 ms and 300 ms.

FIG. 38B is a block diagram of an LED lamp according to an embodiment.Compared to FIG. 38A, ballast-compatible circuit 1510 in the embodimentof FIG. 38B is coupled between pin 503 and/or pin 504 and rectifyingcircuit 540. As explained regarding ballast-compatible circuit 1510 inFIG. 38A, ballast-compatible circuit 1510 in FIG. 38B performs thefunction of delaying the starting of the LED lamp, or causing the inputof the AC driving signal to be delayed for a predefined time, in orderto prevent the failure of starting by lamp driving circuits 505 such asan electronic ballast.

Apart from coupling ballast-compatible circuit 1510 between terminalpin(s) and rectifying circuit in the above embodiments,ballast-compatible circuit 1510 may alternatively be included within arectifying circuit with a different structure. FIG. 38C illustrates anarrangement with a ballast-compatible circuit in an LED lamp accordingto an exemplary embodiment. Referring to FIG. 38C, the rectifyingcircuit assumes the circuit structure of rectifying circuit 810 in FIG.30C. Rectifying circuit 810 includes rectifying unit 815 and terminaladapter circuit 541. Rectifying unit 815 is coupled to pins 501 and 502,terminal adapter circuit 541 is coupled to filtering output terminals511 and 512, and the ballast-compatible circuit 1510 in FIG. 38C iscoupled between rectifying unit 815 and terminal adapter circuit 541. Inthis case, in the initial stage upon activation of the ballast, an ACdriving signal as an external driving signal is input to the LED tubelamp, where the AC driving signal can only reach rectifying unit 815,but cannot reach other circuits such as terminal adapter circuit 541,other internal filter circuitry, and the LED lighting module. Moreover,parasitic capacitors associated with rectifying diodes 811 and 812within rectifying unit 815 are quite small in capacitance and may beignored. Accordingly, lamp driving circuit 505 in the initial stageisn't loaded with or effectively connected to the equivalent capacitoror inductor of the power supply module of the LED lamp, and the qualityfactor (Q) of lamp driving circuit 505 is therefore not adverselyaffected in this stage, resulting in a successful starting of the LEDlamp by lamp driving circuit 505.

It's worth noting that under the condition that terminal adapter circuit541 doesn't include components such as capacitors or inductors,interchanging rectifying unit 815 and terminal adapter circuit 541 inposition, meaning rectifying unit 815 is connected to filtering outputterminals 511 and 512 and terminal adapter circuit 541 is connected topins 501 and 502, doesn't affect or alter the function ofballast-compatible circuit 1510.

Further, as explained in FIGS. 30A˜30D, when a rectifying circuit isconnected to pins 503 and 504 instead of pins 501 and 502, thisrectifying circuit may constitute the rectifying circuit 540. That is,the circuit arrangement with a ballast-compatible circuit 1510 in FIG.38C may be alternatively included in rectifying circuit 540 instead ofrectifying circuit 810, without affecting the function ofballast-compatible circuit 1510.

In some embodiments, as described above terminal adapter circuit 541doesn't include components such as capacitors or inductors. Or whenrectifying circuit 610 in FIG. 30A constitutes the rectifying circuit510 or 540, parasitic capacitances in the rectifying circuit 510 or 540are quite small and may be ignored. These conditions contribute to notaffecting the quality factor of lamp driving circuit 505.

FIG. 38D is a block diagram of an LED lamp according to an embodiment.Compared to the embodiment of FIG. 38A, ballast-compatible circuit 1510in the embodiment of FIG. 38D is coupled between rectifying circuit 540and filtering circuit 520. Since rectifying circuit 540 also doesn'tinclude components such as capacitors or inductors, the function ofballast-compatible circuit 1510 in the embodiment of FIG. 38D will notbe affected.

FIG. 38E is a block diagram of an LED lamp according to an embodiment.Compared to the embodiment of FIG. 38A, ballast-compatible circuit 1510in the embodiment of FIG. 38E is coupled between rectifying circuit 510and filtering circuit 520. Similarly, since rectifying circuit 510doesn't include components such as capacitors or inductors, the functionof ballast-compatible circuit 1510 in the embodiment of FIG. 38E willnot be affected.

FIG. 38F is a schematic diagram of the ballast-compatible circuitaccording to an embodiment. Referring to FIG. 38F, a ballast-compatiblecircuit 1610 has an initial state in which an equivalent open-circuit isobtained at ballast-compatible circuit input and output terminals 1611and 1621. Upon receiving an input signal at ballast-compatible circuitinput terminal 1611, a delay will pass until a current conduction occursthrough and between ballast-compatible circuit input and outputterminals 1611 and 1621, transmitting the input signal toballast-compatible circuit output terminal 1621.

Ballast-compatible circuit 1610 includes a diode 1612, resistors 1613,1615, 1618, 1620, and 1622, a bidirectional triode thyristor (TRIAC)1614, a DIAC or symmetrical trigger diode 1617, a capacitor 1619, andballast-compatible circuit input and output terminals 1611 and 1621.It's noted that the resistance of resistor 1613 should be quite large sothat when bidirectional triode thyristor 1614 is cutoff in anopen-circuit state, an equivalent open-circuit is obtained atballast-compatible circuit input and output terminals 1611 and 1621.

Bidirectional triode thyristor 1614 is coupled betweenballast-compatible circuit input and output terminals 1611 and 1621, andresistor 1613 is also coupled between ballast-compatible circuit inputand output terminals 1611 and 1621 and in parallel to bidirectionaltriode thyristor 1614. Diode 1612, resistors 1620 and 1622, andcapacitor 1619 are serially connected in sequence betweenballast-compatible circuit input and output terminals 1611 and 1621, andare connected in parallel to bidirectional triode thyristor 1614. Diode1612 has an anode connected to bidirectional triode thyristor 1614, andhas a cathode connected to an end of resistor 1620. Bidirectional triodethyristor 1614 has a control terminal connected to a terminal ofsymmetrical trigger diode 1617, which has another terminal connected toan end of resistor 1618, which has another end connected to a nodeconnecting capacitor 1619 and resistor 1622. Resistor 1615 is connectedbetween the control terminal of bidirectional triode thyristor 1614 anda node connecting resistor 1613 and capacitor 1619.

When an AC driving signal (such as a high-frequency high-voltage ACsignal output by an electronic ballast) is initially input toballast-compatible circuit input terminal 1611, bidirectional triodethyristor 1614 will be in an open-circuit state, not allowing the ACdriving signal to pass through and the LED lamp is therefore also in anopen-circuit state. In this state, the AC driving signal is chargingcapacitor 1619 through diode 1612 and resistors 1620 and 1622, graduallyincreasing the voltage of capacitor 1619. After charging continually,the voltage of capacitor 1619 increases to a level above the triggervoltage value of symmetrical trigger diode 1617 so that symmetricaltrigger diode 1617 is turned on in a conducting state. Then theconducting symmetrical trigger diode 1617 will in turn triggerbidirectional triode thyristor 1614 on in a conducting state. In thissituation, the conducting bidirectional triode thyristor 1614electrically connects ballast-compatible circuit input and outputterminals 1611 and 1621, allowing the AC driving signal to flow throughballast-compatible circuit input and output terminals 1611 and 1621, andstarting the operation of the power supply module of the LED lamp. Inthis case the energy stored by capacitor 1619 will maintain theconducting state of bidirectional triode thyristor 1614, to prevent theAC variation of the AC driving signal from causing bidirectional triodethyristor 1614 and therefore ballast-compatible circuit 1610 to becutoff again, or to prevent the problem of bidirectional triodethyristor 1614 alternating or switching between its conducting andcutoff states.

In general, in hundreds of milliseconds upon activation of a lampdriving circuit 505 such as an electronic ballast, the output voltage ofthe ballast has risen above a certain voltage value as the outputvoltage hasn't been adversely affected by the sudden initial loadingfrom the LED lamp. A detection mechanism to detect whether lighting of afluorescent lamp is achieved may be disposed in lamp driving circuits505 such as an electronic ballast. In this detection mechanism, if afluorescent lamp fails to light up for a determined period, an abnormalstate of the fluorescent lamp is detected, causing the fluorescent lampto enter a protection state. In certain embodiments, the delay providedby ballast-compatible circuit 1610 until conduction ofballast-compatible circuit 1610 and then the LED lamp may be in therange of about 0.1˜3 seconds.

It's worth noting that an additional capacitor 1623 may be coupled inparallel to resistor 1622. Capacitor 1623 works to reflect or supportinstantaneous change in the voltage between ballast-compatible circuitinput and output terminals 1611 and 1621, and will not affect thefunction of delayed conduction performed by ballast-compatible circuit1610.

FIG. 38G is a block diagram of a power supply system in an LED lampaccording to an embodiment. Compared to the embodiment of FIG. 29C, lampdriving circuit 505 in the embodiment of FIG. 38G drives a plurality ofLED tube lamps 500 connected in series, wherein a ballast-compatiblecircuit 1610 is disposed in each of the LED tube lamps 500. For theconvenience of illustration, two serially connected LED tube lamps 500are assumed for example and explained as follows.

Because the two ballast-compatible circuits 1610 respectively of the twoLED tube lamps 500 potentially have different delays until conduction ofthe LED tube lamps 500, due to various factors such as errors occurringin production processes of some components, the actual timing ofconduction of each of the ballast-compatible circuits 1610 is different.Upon activation of a lamp driving circuit 505, the voltage of the ACdriving signal provided by lamp driving circuit 505 will be shared outby the two LED tube lamps 500 roughly equally. Subsequently when onlyone of the two LED tube lamps 500 first enters a conducting state, thevoltage of the AC driving signal then will be borne mostly or entirelyby the other LED tube lamp 500. This situation will cause the voltageacross the ballast-compatible circuits 1610 in the other LED tube lamp500 that's not conducting to suddenly increase or be doubled, meaningthe voltage between ballast-compatible circuit input and outputterminals 1611 and 1621 might even be suddenly doubled. In view of this,if capacitor 1623 is included, the voltage division effect betweencapacitors 1619 and 1623 will instantaneously increase the voltage ofcapacitor 1619, making symmetrical trigger diode 1617 triggeringbidirectional triode thyristor 1614 into a conducting state, and causingthe two ballast-compatible circuits 1610 respectively of the two LEDtube lamps 500 to become conducting almost at the same time. Therefore,by introducing capacitor 1623, the situation, where one of the twoballast-compatible circuits 1610 respectively of the two seriallyconnected LED tube lamps 500 that is first conducting has itsbidirectional triode thyristor 1614 then suddenly cutoff as havinginsufficient current passing through due to the discrepancy between thedelays provided by the two ballast-compatible circuits 1610 until theirrespective conductions, can be avoided. Therefore, using eachballast-compatible circuit 1610 with capacitor 1623 further improves thecompatibility of the serially connected LED tube lamps with each of lampdriving circuits 505 such as an electronic ballast.

An exemplary range of the capacitance of capacitor 1623 may be about 10pF to about 1 nF. In some embodiments, the range of the capacitance ofcapacitor 1623 may be about 10 pF to about 100 pF. For example, thecapacitance of capacitor 1623 may be about 47 pF.

It's worth noting that diode 1612 is used or configured to rectify thesignal for charging capacitor 1619. Therefore, with reference to FIGS.38C, 38D, and 38E, in the case when ballast-compatible circuit 1610 isarranged following a rectifying unit or circuit, diode 1612 may beomitted. Diode 1612 is depicted by a dotted line in FIG. 38F.

FIG. 38H is a schematic diagram of the ballast-compatible circuitaccording to another embodiment. Referring to FIG. 38H, aballast-compatible circuit 1710 has an initial state in which anequivalent open-circuit is obtained at ballast-compatible circuit inputand output terminals 1711 and 1721. Upon receiving an input signal atballast-compatible circuit input terminal 1711, ballast-compatiblecircuit 1710 will be in a cutoff state when the level of the inputexternal driving signal is below a defined value corresponding to aconduction delay of ballast-compatible circuit 1710; andballast-compatible circuit 1710 will enter a conducting state upon thelevel of the input external driving signal reaching the defined value,thus transmitting the input signal to ballast-compatible circuit outputterminal 1721.

Ballast-compatible circuit 1710 includes a bidirectional triodethyristor (TRIAC) 1712, a DIAC or symmetrical trigger diode 1713,resistors 1714, 1716, and 1717, and a capacitor 1715. Bidirectionaltriode thyristor 1712 has a first terminal connected toballast-compatible circuit input terminal 1711; a control terminalconnected to a terminal of symmetrical trigger diode 1713 and an end ofresistor 1714; and a second terminal connected to another end ofresistor 1714. Capacitor 1715 has an end connected to another terminalof symmetrical trigger diode 1713, and has another end connected to thesecond terminal of bidirectional triode thyristor 1712. Resistor 1717 isin parallel connection with capacitor 1715, and is therefore alsoconnected to said another terminal of symmetrical trigger diode 1713 andthe second terminal of bidirectional triode thyristor 1712. And resistor1716 has an end connected to the node connecting capacitor 1715 andsymmetrical trigger diode 1713, and has another end connected toballast-compatible circuit output terminal 1721.

When an AC driving signal (such as a high-frequency high-voltage ACsignal output by an electronic ballast) is initially input toballast-compatible circuit input terminal 1711, bidirectional triodethyristor 1712 will be in an open-circuit state, not allowing the ACdriving signal to pass through and the LED lamp is therefore also in anopen-circuit state. The input of the AC driving signal causes apotential difference between ballast-compatible circuit input terminal1711 and ballast-compatible circuit output terminal 1721. When the ACdriving signal increases with time to eventually reach a sufficientamplitude (which is a defined level after the delay) after a period oftime, the signal level at ballast-compatible circuit output terminal1721 has a reflected voltage at the control terminal of bidirectionaltriode thyristor 1712 after passing through resistor 1716,parallel-connected capacitor 1715 and resistor 1717, and resistor 1714,wherein the reflected voltage then triggers bidirectional triodethyristor 1712 into a conducting state. This conducting state makesballast-compatible circuit 1710 entering a conducting state which causesthe LED lamp to operate normally. Upon bidirectional triode thyristor1712 conducting, a current flows through resistor 1716 and then chargescapacitor 1715 to store a specific voltage on capacitor 1715. In thiscase, the energy stored by capacitor 1715 will maintain the conductingstate of bidirectional triode thyristor 1712, to prevent the ACvariation of the AC driving signal from causing bidirectional triodethyristor 1712 and therefore ballast-compatible circuit 1710 to becutoff again, or to prevent the situation of bidirectional triodethyristor 1712 alternating or switching between its conducting andcutoff states.

FIG. 38I illustrates the ballast-compatible circuit according to anembodiment. Referring to FIG. 38I, a ballast-compatible circuit 1810includes a housing 1812, a metallic electrode 1813, a bimetallic strip1814, and a heating filament 1816. Metallic electrode 1813 and heatingfilament 1816 protrude from the housing 1812, so that they each have aportion inside the housing 1812 and a portion outside of the housing1812. Metallic electrode 1813's outside portion has a ballast-compatiblecircuit input terminal 1811, and heating filament 1816's outside portionhas a ballast-compatible circuit output terminal 1821. Housing 1812 ishermetic or tightly sealed and contains inert gas 1815 such as heliumgas. Bimetallic strip 1814 is inside housing 1812 and is physically andelectrically connected to the portion of heating filament 1816 that isinside the housing 1812. And there is a spacing between bimetallic strip1814 and metallic electrode 1813, so that ballast-compatible circuitinput terminal 1811 and ballast-compatible circuit output terminal 1821are not electrically connected in the initial state ofballast-compatible circuit 1810. Bimetallic strip 1814 may include twometallic strips with different temperature coefficients, wherein themetallic strip closer to metallic electrode 1813 has a smallertemperature coefficient, and the metallic strip more away from metallicelectrode 1813 has a larger temperature coefficient.

When an AC driving signal (such as a high-frequency high-voltage ACsignal output by an electronic ballast) is initially input atballast-compatible circuit input terminal 1811 and ballast-compatiblecircuit output terminal 1821, a potential difference between metallicelectrode 1813 and heating filament 1816 is formed. When the potentialdifference increases enough to cause electric arc or arc dischargethrough inert gas 1815, meaning when the AC driving signal increaseswith time to eventually reach the defined level after a delay, theninert gas 1815 is then heated to cause bimetallic strip 1814 to swelltoward metallic electrode 1813 (as in the direction of the broken-linearrow in FIG. 38I), with this swelling eventually causing bimetallicstrip 1814 to bear against metallic electrode 1813, forming the physicaland electrical connections between them. In this situation, there iselectrical conduction between ballast-compatible circuit input terminal1811 and ballast-compatible circuit output terminal 1821. Then the ACdriving signal flows through and heats heating filament 1816. In thisheating process, heating filament 1816 allows a current to flow throughwhen electrical conduction exists between metallic electrode 1813 andbimetallic strip 1814, causing the temperature of bimetallic strip 1814to be above a defined conduction temperature. As a result, since therespective temperature of the two metallic strips of bimetallic strip1814 with different temperature coefficients are maintained above thedefined conduction temperature, bimetallic strip 1814 will bend againstor toward metallic electrode 1813, thus maintaining or supporting thephysical joining or connection between bimetallic strip 1814 andmetallic electrode 1813.

Therefore, upon receiving an input signal at ballast-compatible circuitinput and output terminals 1811 and 1821, a delay will pass until anelectrical/current conduction occurs through and betweenballast-compatible circuit input and output terminals 1811 and 1821.

Therefore, an exemplary ballast-compatible circuit such as describedherein may be coupled between any pin and any rectifying circuitdescribed above, wherein the ballast-compatible circuit will be in acutoff state in a defined delay upon an external driving signal beinginput to the LED tube lamp, and will enter a conducting state after thedelay. Otherwise, the ballast-compatible circuit will be in a cutoffstate when the level of the input external driving signal is below adefined value corresponding to a conduction delay of theballast-compatible circuit; and ballast-compatible circuit will enter aconducting state upon the level of the input external driving signalreaching the defined value. Accordingly, the compatibility of the LEDtube lamp described herein with lamp driving circuits 505 such as anelectronic ballast is further improved by using such aballast-compatible circuit.

FIG. 39A is a block diagram of an LED tube lamp according to anembodiment. Compared to that shown in FIG. 29D, the present embodimentcomprises the rectifying circuits 510 and 540, and the filtering circuit520, and further comprises two ballast-compatible circuits 1540; whereinthe power supply module may also include some components of LED lightingmodule 530. The two ballast-compatible circuits 1540 are coupledrespectively between the pin 503 and the rectifying output terminal 511and between the pin 504 and the rectifying output terminal 511.Referring to FIG. 29A and FIG. 29C, the lamp driving circuit 505 is anelectronic ballast for supplying an AC driving signal to drive the LEDlamp.

Two ballast-compatible circuits 1540 are initially in conducting states,and then enter cutoff state in a delay. Therefore, in an initial stageupon activation of the lamp driving circuit 505, the AC driving signalis transmitted through the pin 503, the corresponding ballast-compatiblecircuit 1540, the rectifying output terminal 511 and the rectifyingcircuit 510, or through the pin 504, the correspondingballast-compatible circuit 1540, the rectifying output terminal 511 andthe rectifying circuit 510 of the LED lamp, and the filtering circuit520 and LED lighting module 530 of the LED lamp are bypassed. Thereby,the LED lamp presents almost no load and does not affect the qualityfactor of the lamp driving circuit 505 at the beginning, and so the lampdriving circuit can be activated successfully. The twoballast-compatible circuits 1540 are cut off for a moment while the lampdriving circuit 505 has been activated successfully. After that, thelamp driving circuit 505 has a sufficient drive capability for drivingthe LED lamp to emit light.

FIG. 39B is a block diagram of an LED tube lamp according to anembodiment. Compared to that shown in FIG. 39A, the twoballast-compatible circuits 1540 are changed to be coupled respectivelybetween the pin 503 and the rectifying output terminal 512 and betweenthe pin 504 and the rectifying output terminal 512. Similarly, twoballast-compatible circuits 1540 are initially in conducting states, andthen changed to cutoff states after an objective delay. Thereby, thelamp driving circuit 505 drives the LED lamp to emit light after thelamp driving circuit 505 has activated.

It is worth noting that the arrangement of the two ballast-compatiblecircuits 1540 may be changed to be coupled between the pin 501 and therectifying terminal 511 and between the pin 501 and the rectifyingterminal 511, or between the pin 501 and the rectifying terminal 512 andbetween the pin 501 and the rectifying terminal 512, for having the lampdriving circuit 505 drive the LED lamp to emit light after beingactivated.

FIG. 39C is a block diagram of an LED tube lamp according to anembodiment. Compared to that shown in FIGS. 39A and 39B, the rectifyingcircuit 810 shown in FIG. 30C replaces the rectifying circuit 540, andthe rectifying unit 815 of the rectifying circuit 810 is coupled to thepins 503 and 504 and the terminal adapter circuit 541 thereof is coupledto the rectifying output terminals 511 and 512. The arrangement of thetwo ballast-compatible circuits 1540 is also changed to be coupledrespectively between the pin 501 and the half-wave node 819 and betweenthe pin 502 and the half-wave node 819. It's noted that the terminaladapter circuit is for transmitting (intended to encompass the meaningsof “changing” and “transforming”) the external driving signal receivedat the pin 501 and/or the pin 502.

In an initial stage upon activation of the lamp driving circuit 505, twoballast-compatible circuits 1540 are initially in conducting states. Atthis moment, the AC driving signal is transmitted through the pin 501,the corresponding ballast-compatible circuit 1540, the half-wave node819 and the rectifying unit 815 or the pin 502, the correspondingballast-compatible circuit 1540, the half-wave node 819 and therectifying unit 815 of the LED lamp, and the terminal adapter circuit541, the filtering circuit 520 and LED lighting module 530 of the LEDlamp are bypassed. Thereby, the LED lamp presents almost no load anddoes not affect the quality factor of the lamp driving circuit 505 atthe beginning, and so the lamp driving circuit can be activatedsuccessfully. The two ballast-compatible circuits 1540 are cut off for amoment while the lamp driving circuit 505 has been activatedsuccessfully. After that, the lamp driving circuit 505 has a sufficientdrive capability for driving the LED lamp to emit light.

It is worth noting that the rectifying circuit 810 shown in FIG. 30C mayreplace the rectifying circuit 510 of the present embodiment shown inFIG. 39C instead of the rectifying circuit 540. Wherein, the rectifyingunit 815 of the rectifying circuit 810 is coupled to the pins 501 and502 and the terminal adapter circuit 541 thereof is coupled to therectifying output terminals 511 and 512. The arrangement of the twoballast-compatible circuits 1540 is also changed to be coupledrespectively between the pin 503 and the half-wave node 819 and betweenthe pin 504 and the half-wave node 819.

FIG. 39D is a schematic diagram of a ballast-compatible circuitaccording to an embodiment, which is applicable to the embodiments shownin FIGS. 39A and 39B and the described modification thereof.

A ballast-compatible circuit 1640 comprises resistors 1643, 1645, 1648and 1650, capacitors 1644 and 1649, diodes 1647 and 1652, bipolarjunction transistors (BJT) 1646 and 1651, a ballast-compatible circuitterminal 1641 and a ballast-compatible circuit terminal 1642. One end ofthe resistor 1645 is coupled to the ballast-compatible circuit terminal1641, and the other end is coupled to an emitter of the BJT 1646. Acollector of the BJT 1646 is coupled to a positive end of the diode1647, and a negative end thereof is coupled to the ballast-compatiblecircuit terminal 1642. The resistor 1643 and the capacitor 1644 areconnected in series with each other and coupled between the emitter andthe collector of the BJT 1646, and the connection node of the resistor1643 and the capacitor 1644 is coupled to a base of the BJT 1646. Oneend of the resistor 1650 is coupled to the ballast-compatible circuitterminal 1642, and the other end is coupled to an emitter of the BJT1651. A collector of the BJT 1651 is coupled to a positive end of thediode 1652, and a negative end thereof is coupled to theballast-compatible circuit terminal 1641. The resistor 1648 and thecapacitor 1649 are connected in series with each other and coupledbetween the emitter and the collector of the BJT 1651, and theconnection node of the resistor 1648 and the capacitor 1649 is coupledto a base of the BJT 1651.

In an initial stage upon the lamp driving circuit 505, e.g. electronicballast, being activated, voltages across the capacitors 1644 and 1649are about zero. At this point, the BJTs 1646 and 1651 are in conductingstate and the bases thereof allow currents to flow through. Therefore,in an initial stage upon activation of the lamp driving circuit 505, theballast-compatible circuits 1640 are in conducting state. The AC drivingsignal charges the capacitor 1644 through the resistor 1643 and thediode 1647, and charges the capacitor 1649 through the resistor 1648 andthe diode 1652. In a moment, the voltages across the capacitors 1644 and1649 reach certain voltages for reducing the voltages of the resistors1643 and 1648, thereby cutting off the BJTs 1646 and 1651, i.e., thestates of the BJTs 1646 and 1651 are cutoff states. At this point, thestate of the ballast-compatible circuit 1640 is changed to the cutoffstate. Thereby, the internal capacitor(s) and inductor(s) do not affectin Q-factor of the lamp driving circuit 505 at the beginning forensuring the lamp driving circuit activating. Hence, theballast-compatible circuit 1640 improves the compatibility of LED lampwith the electronic ballast.

In summary, the two ballast-compatible circuits are respectively coupledbetween a connection node of the rectifying circuit and the filteringcircuit (i.e., the rectifying output terminal 511 or 512) and the pin501 and between the connection node and the pin 502, or coupled betweenthe connection node and the pin 503 and the connection node and the pin504. The two ballast-compatible circuits conduct for an objective delayupon the external driving signal being input into the LED tube lamp, andthen are cut off for enhancing the compatibility of the LED lamp withthe electronic ballast.

FIG. 40A is a block diagram of an LED tube lamp according to anembodiment. Compared to that shown in FIG. 29D, the present embodimentcomprises the rectifying circuits 510 and 540, the filtering circuit520, and the LED lighting module 530, and further comprises twofilament-simulating circuits 1560. The filament-simulating circuits 1560are respectively coupled between the pins 501 and 502 and coupledbetween the pins 503 and 504, for improving a compatibility with a lampdriving circuit having filament detection function, e.g.: program-startballast.

In an initial stage upon the lamp driving circuit having filamentdetection function being activated, the lamp driving circuit willdetermine whether the filaments of the lamp operate normally or are inan abnormal condition of short-circuit or open-circuit. When determiningthe abnormal condition of the filaments, the lamp driving circuit stopsoperating and enters a protection state. In order to avoid that the lampdriving circuit erroneously determines the LED tube lamp to be abnormaldue to the LED tube lamp having no filament, the two filament-simulatingcircuits 1560 simulate the operation of actual filaments of afluorescent tube to have the lamp driving circuit enter into a normalstate to start the LED lamp normally.

FIG. 40B is a schematic diagram of a filament-simulating circuitaccording to an embodiment. The filament-simulating circuit comprises acapacitor 1663 and a resistor 1665 connected in parallel, and two endsof the capacitor 1663 and two ends of the resistor 1665 are rerespectively coupled to filament simulating terminals 1661 and 1662.Referring to FIG. 40A, the two filament-simulating terminals 1661 and1662 of the filament-simulating circuit 1660 are respectively coupled tothe pins 501 and 502 and the pins 503 and 504. During the filamentdetection process, the lamp driving circuit outputs a detection signalto detect the state of the filaments. The detection signal passes thecapacitor 1663 and the resistor 1665 and so the lamp driving circuitdetermines that the filaments of the LED lamp are normal.

In addition, a capacitance value of the capacitor 1663 is low and so acapacitive reactance (equivalent impedance) of the capacitor 1663 is farlower than an impedance of the resistor 1665 due to the lamp drivingcircuit outputting a high-frequency alternative current (AC) signal todrive LED lamp. Therefore, the filament-simulating circuit 1660 consumesrelatively little power when the LED lamp operates normally, and so italmost does not affect the luminous efficiency of the LED lamp.

FIG. 40C is a schematic block diagram including a filament-simulatingcircuit according to an embodiment. In the present embodiment, thefilament-simulating circuit 1660 replaces the terminal adapter circuit541 of the rectifying circuit 810 shown in FIG. 30C, which is adopted asthe rectifying circuit 510 or/and 540 in the LED lamp. For example, thefilament-simulating circuit 1660 of the present embodiment has both offilament simulating and terminal adapting functions. Referring to FIG.40A, the filament simulating terminals 1661 and 1662 of thefilament-simulating circuit 1660 are respectively coupled to the pins501 and 502 or/and pins 503 and 504. The half-wave node 819 ofrectifying unit 815 in the rectifying circuit 810 is coupled to thefilament simulating terminal 1662.

FIG. 40D is a schematic block diagram including a filament-simulatingcircuit according to another embodiment. Compared to that shown in FIG.40C, the half-wave node is changed to be coupled to the filamentsimulating terminal 1661, and the filament-simulating circuit 1660 inthe present embodiment still has both of filament simulating andterminal adapting functions.

FIG. 40E is a schematic diagram of a filament-simulating circuitaccording to another embodiment. A filament-simulating circuit 1760comprises capacitors 1763 and 1764, and the resistors 1765 and 1766. Thecapacitors 1763 and 1764 are connected in series and coupled between thefilament simulating terminals 1661 and 1662. The resistors 1765 and 1766are connected in series and coupled between the filament simulatingterminals 1661 and 1662. Furthermore, the connection node of capacitors1763 and 1764 is coupled to that of the resistors 1765 and 1766.Referring to FIG. 40A, the filament simulating terminals 1661 and 1662of the filament-simulating circuit 1760 are respectively coupled to thepins 501 and 502 and the pins 503 and 504. When the lamp driving circuitoutputs the detection signal for detecting the state of the filament,the detection signal passes the capacitors 1763 and 1764 and theresistors 1765 and 1766 so that the lamp driving circuit determines thatthe filaments of the LED lamp are normal.

It is worth noting that in some embodiments, capacitance values of thecapacitors 1763 and 1764 are low and so a capacitive reactance of theserially connected capacitors 1763 and 1764 is far lower than animpedance of the serially connected resistors 1765 and 1766 due to thelamp driving circuit outputting the high-frequency AC signal to driveLED lamp. Therefore, the filament-simulating circuit 1760 consumeslittle power when the LED lamp operates normally, and so it almost doesnot affect the luminous efficiency of the LED lamp. Moreover, any one ofthe capacitor 1763 and the resistor 1765 is short circuited or is anopen circuit, or any one of the capacitor 1764 and the resistor 1766 isshort circuited or is an open circuit, the detection signal still passesthrough the filament-simulating circuit 1760 between the filamentsimulating terminals 1661 and 1662. Therefore, the filament-simulatingcircuit 1760 still operates normally when any one of the capacitor 1763and the resistor 1765 is short circuited or is an open circuit or anyone of the capacitor 1764 and the resistor 1766 is short circuited or isan open circuit, and so it has quite high fault tolerance.

FIG. 40F is a schematic block diagram including a filament-simulatingcircuit according to an embodiment. In the present embodiment, thefilament-simulating circuit 1860 replaces the terminal adapter circuit541 of the rectifying circuit 810 shown in FIG. 30C, which is adopted asthe rectifying circuit 510 or/and 540 in the LED lamp. For example, thefilament-simulating circuit 1860 of the present embodiment has both offilament simulating and terminal adapting functions. An impedance of thefilament-simulating circuit 1860 has a negative temperature coefficient(NTC), i.e., the impedance at a higher temperature is lower than that ata lower temperature. In the present embodiment, the filament-simulatingcircuit 1860 comprises two NTC resistors 1863 and 1864 connected inseries and coupled to the filament simulating terminals 1661 and 1662.Referring to FIG. 40A, the filament simulating terminals 1661 and 1662are respectively coupled to the pins 501 and 502 or/and the pins 503 and504. The half-wave node 819 of the rectifying unit 815 in the rectifyingcircuit 810 is coupled to a connection node of the NTC resistors 1863and 1864.

When the lamp driving circuit outputs the detection signal for detectingthe state of the filament, the detection signal passes the NTC resistors1863 and 1864 so that the lamp driving circuit determines that thefilaments of the LED lamp are normal. The impedance of the seriallyconnected NTC resistors 1863 and 1864 is gradually decreased with thegradually increasing of temperature due to the detection signal or apreheat process. When the lamp driving circuit enters into the normalstate to start the LED lamp normally, the impedance of the seriallyconnected NTC resistors 1863 and 1864 is decreased to a relative lowvalue and so the power consumption of the filament simulation circuit1860 is lower.

An exemplary impedance of the filament-simulating circuit 1860 can be 10ohms or more at room temperature (25 degrees Celsius) and may bedecreased to a range of about 2-10 ohms when the lamp driving circuitenters the normal state. In some embodiments, the impedance of thefilament-simulating circuit 1860 may be decreased to a range of about3-6 ohms when the lamp driving circuit enters the normal state.

FIG. 41A is a block diagram of an LED tube lamp according to anembodiment. Compared to that shown in FIG. 29D, the present embodimentcomprises the rectifying circuits 510 and 540, the filtering circuit520, and the LED lighting module 530, and further comprises an overvoltage protection (OVP) circuit 1570. The OVP circuit 1570 is coupledto the filtering output terminals 521 and 522 for detecting the filteredsignal. The OVP circuit 1570 clamps the level of the filtered signalwhen determining the level thereof higher than a defined OVP value.Hence, the OVP circuit 1570 protects the LED lighting module 530 fromdamage due to an OVP condition. The rectifying circuit 540 may beomitted and is therefore depicted by a dotted line.

FIG. 41B is a schematic diagram of an overvoltage protection (OVP)circuit according to an embodiment. The OVP circuit 1670 comprises avoltage clamping diode 1671, such as Zener diode, coupled to thefiltering output terminals 521 and 522. The voltage clamping diode 1671is conducted to clamp a voltage difference at a breakdown voltage whenthe voltage difference of the filtering output terminals 521 and 522(i.e., the level of the filtered signal) reaches the breakdown voltage.The breakdown voltage may be in a range of about 40 V to about 100 V. Insome embodiments, the breakdown voltage may be in a range of about 55 Vto about 75V.

FIG. 42A is a block diagram of an LED tube lamp according to anembodiment. Compared to that shown in FIG. 40A, the present embodimentcomprises the rectifying circuits 510 and 540, the filtering circuit520, the LED lighting module 530 and the two filament-simulatingcircuits 1560, and further comprises a ballast detection circuit 1590.The ballast detection circuit 1590 may be coupled to any one of the pins501, 502, 503 and 504 and a corresponding rectifying circuit of therectifying circuits 510 and 540. In the present embodiment, the ballastdetection circuit 1590 is coupled between the pin 501 and the rectifyingcircuit 510.

The ballast detection circuit 1590 detects the AC driving signal or asignal input through the pins 501, 502, 503 and 504, and determineswhether the input signal is provided by an electric ballast based on thedetected result.

FIG. 42B is a block diagram of an LED tube lamp according to anembodiment. Compared to that shown in FIG. 42A, the rectifying circuit810 shown in FIG. 30C replaces the rectifying circuit 510. The ballastdetection circuit 1590 is coupled between the rectifying unit 815 andthe terminal adapter circuit 541. One of the rectifying unit 815 and theterminal adapter circuit 541 is coupled to the pines 503 and 504, andthe other one is coupled to the rectifying output terminal 511 and 512.In the present embodiment, the rectifying unit 815 is coupled to thepins 503 and 504, and the terminal adapter circuit 541 is coupled to therectifying output terminal 511 and 512. Similarly, the ballast detectioncircuit 1590 detects the signal input through the pins 503 and 504 fordetermining the input signal whether provided by an electric ballastaccording to the frequency of the input signal.

In addition, the rectifying circuit 810 may replace the rectifyingcircuit 510 instead of the rectifying circuit 540, and the ballastdetection circuit 1590 is coupled between the rectifying unit 815 andthe terminal adapter circuit 541 in the rectifying circuit 510.

FIG. 42C is a block diagram of a ballast detection circuit according toan embodiment. The ballast detection circuit 1590 comprises a detectioncircuit 1590 a and a switch circuit 1590 b. The switch circuit 1590 b iscoupled to switch terminals 1591 and 1592. The detection circuit 1590 ais coupled to the detection terminals 1593 and 1594 for detecting asignal transmitted through the detection terminals 1593 and 1594.Alternatively, the switch terminals 1591 and 1592 serves as thedetection terminals and the detection terminals 1593 and 1594 areomitted. For example, in certain embodiments, the switch circuit 1590 band the detection circuit 1590 a are commonly coupled to the switchterminals 1591 and 1592, and the detection circuit 1590 a detects asignal transmitted through the switch terminals 1591 and 1592. Hence,the detection terminals 1593 and 1594 are depicted by dotted lines.

FIG. 42D is a schematic diagram of a ballast detection circuit accordingto an embodiment. The ballast detection circuit 1690 comprises adetection circuit 1690 a and a switch circuit 1690 b, and is coupledbetween the switch terminals 1591 and 1592. The detection circuit 1690 acomprises a symmetrical trigger diode 1691, resistors 1692 and 1696 andcapacitors 1693, 1697 and 1698. The switch circuit 1690 b comprises aTRIAC 1699 and an inductor 1694.

The capacitor 1698 is coupled between the switch terminals 1591 and 1592for generating a detection voltage in response to a signal transmittedthrough the switch terminals 1591 and 1592. When the signal is a highfrequency signal, the capacitive reactance of the capacitor 1698 isfairly low and so the detection voltage generated thereby is quite high.The resistor 1692 and the capacitor 1693 are connected in series andcoupled between two ends of the capacitor 1698. The serially connectedresistor 1692 and the capacitor 1693 is used to filter the detectionsignal generated by the capacitor 1698 and generates a filtereddetection signal at a connection node thereof. The filter function ofthe resistor 1692 and the capacitor 1693 is used to filter highfrequency noise in the detection signal for preventing the switchcircuit 1690 b from malfunctioning due to the high frequency noise. Theresistor 1696 and the capacitor 1697 are connected in series and coupledbetween two ends of the capacitor 1693, and transmit the filtereddetection signal to one end of the symmetrical trigger diode 1691. Theserially connected resistor 1696 and capacitor 1697 performs secondfiltering of the filtered detection signal to enhance the filter effectof the detection circuit 1690 a. Based on requirement for filteringlevel of different application, the capacitor 1697 may be omitted andthe end of the symmetrical trigger diode 1691 is coupled to theconnection node of the resistor 1692 and the capacitor 1693 through theresistor 1696. Alternatively, both of the resistor 1696 and thecapacitor 1697 are omitted and the end of the symmetrical trigger diode1691 is directly coupled to the connection node of the resistor 1692 andthe capacitor 1693. Therefore, the resistor 1696 and the capacitor 1697are depicted by dotted lines. The other end of the symmetrical triggerdiode 1691 is coupled to a control end of the TRIAC 1699 of the switchcircuit 1690 b. The symmetrical trigger diode 1691 determines whether togenerate a control signal 1695 to trigger the TRIAC 1699 on according toa level of a received signal. A first end of the TRIAC 1699 is coupledto the switch terminal 1591 and a second end thereof is coupled to theswitch terminal through the inductor 1694. The inductor 1694 is used toprotect the TRIAC 1699 from damage due to a situation where the signaltransmitted into the switch terminals 1591 and 1592 is over a maximumrate of rise of Commutation Voltage, a peak repetitive forward(off-state) voltage or a maximum rate of change of current.

When the switch terminals 1591 and 1592 receive a low frequency signalor a DC signal, the detection signal generated by the capacitor 1698 ishigh enough to make the symmetrical trigger diode 1691 generate thecontrol signal 1695 to trigger the TRIAC 1699 on. At the same time, theswitch terminals 1591 and 1592 are shorted to bypass the circuit(s)connected in parallel with the switch circuit 1690 b, such as a circuitcoupled between the switch terminals 1591 and 1592, the detectioncircuit 1690 a and the capacitor 1698.

In some embodiments, when the switch terminals 1591 and 1592 receive ahigh frequency AC signal, the detection signal generated by thecapacitor 1698 is not high enough to make the symmetrical trigger diode1691 generate the control signal 1695 to trigger the TRIAC 1699 on. Atthe same time, the TRIAC 1699 is cut off and so the high frequency ACsignal is mainly transmitted through external circuit or the detectioncircuit 1690 a.

Hence, the ballast detection circuit 1690 can determine whether theinput signal is a high frequency AC signal provided by an electricballast. If yes, the high frequency AC signal is transmitted through theexternal circuit or the detection circuit 1690 a; if no, the inputsignal is transmitted through the switch circuit 1690 b, bypassing theexternal circuit and the detection circuit 1690 a.

It is worth noting that the capacitor 1698 may be replaced by externalcapacitor(s), such as at least one capacitor in the terminal adaptercircuits shown in FIG. 31A-C. Therefore, the capacitor 1698 may beomitted and be therefore depicted by a dotted line.

FIG. 42E is a schematic diagram of a ballast detection circuit accordingto an embodiment. The ballast detection circuit 1790 comprises adetection circuit 1790 a and a switch circuit 1790 b. The switch circuit1790 b is coupled between the switch terminals 1591 and 1592. Thedetection circuit 1790 a is coupled between the detection terminals 1593and 1594. The detection circuit 1790 a comprises inductors 1791 and 1792with mutual induction, capacitor 1793 and 1796, a resistor 1794 and adiode 1797. The switch circuit 1790 b comprises a switch 1799. In thepresent embodiment, the switch 1799 is a P-type Depletion Mode MOSFET,which is cut off when the gate voltage is higher than a thresholdvoltage and conducted when the gate voltage is lower than the thresholdvoltage.

The inductor 1792 is coupled between the detection terminals 1593 and1594 and induces a detection voltage in the inductor 1791 based on acurrent signal flowing through the detection terminals 1593 and 1594.The level of the detection voltage is varied with the frequency of thecurrent signal, and may be increased with the increasing of thatfrequency and reduced with the decreasing of that frequency.

In some embodiments, when the signal is a high frequency signal, theinductive reactance of the inductor 1792 is quite high and so theinductor 1791 induces the detection voltage with a quite high level.When the signal is a low frequency signal or a DC signal, the inductivereactance of the inductor 1792 is quite low and so the inductor 1791induces the detection voltage with a quite high level. One end of theinductor 1791 is grounded. The serially connected capacitor 1793 andresistor 1794 is connected in parallel with the inductor 1791. Thecapacitor 1793 and resistor 1794 receive the detection voltage generatedby the inductor 1791 and filter a high frequency component of thedetection voltage to generate a filtered detection voltage. The filtereddetection voltage charges the capacitor 1796 through the diode 1797 togenerate a control signal 1795. Due to the diode 1797 providing aone-way charge for the capacitor 1796, the level of control signalgenerated by the capacitor 1796 is the maximum value of the detectionvoltage. The capacitor 1796 is coupled to the control end of the switch1799. First and second ends of the switch 1799 are respectively coupledto the switch terminals 1591 and 1592.

When the signal received by the detection terminal 1593 and 1594 is alow frequency signal or a DC signal, the control signal 1795 generatedby the capacitor 1796 is lower than the threshold voltage of the switch1799 and so the switch 1799 are conducted. At the same time, the switchterminals 1591 and 1592 are shorted to bypass the external circuit(s)connected in parallel with the switch circuit 1790 b, such as the leastone capacitor in the terminal adapter circuits show in FIG. 31A-c.

When the signal received by the detection terminal 1593 and 1594 is ahigh frequency signal, the control signal 1795 generated by thecapacitor 1796 is higher than the threshold voltage of the switch 1799and so the switch 1799 are cut off. At the same time, the high frequencysignal is transmitted by the external circuit(s).

Hence, the ballast detection circuit 1790 can determine whether theinput signal is a high frequency AC signal provided by an electricballast. If yes, the high frequency AC signal is transmitted through theexternal circuit(s); if no, the input signal is transmitted through theswitch circuit 1790 b, bypassing the external circuit.

Next, exemplary embodiments of the conduction (bypass) and cut off (notbypass) operations of the switch circuit in the ballast detectioncircuit of an LED lamp will be illustrated. For example, the switchterminals 1591 and 1592 are coupled to a capacitor connected in serieswith the LED lamp, e.g., a signal for driving the LED lamp also flowsthrough the capacitor. The capacitor may be disposed inside the LED lampto be connected in series with internal circuit(s) or outside the LEDlamp to be connected in series with the LED lamp. Referring to FIG. 29Aor 29C, the AC power supply 508 provides a low voltage and low frequencyAC driving signal as an external driving signal to drive the LED tubelamp 500 while the lamp driving circuit 505 does not exist. At thismoment, the switch circuit of the ballast detection circuit isconducted, and so the alternative driving signal is provided to directlydrive the internal circuits of the LED tube lamp 500. When the lampdriving circuit 505 exists, the lamp driving circuit 505 provides a highvoltage and high frequency AC driving signal as an external drivingsignal to drive the LED tube lamp 500. At this moment, the switchcircuit of the ballast detection circuit is cut off, and so thecapacitor is connected in series with an equivalent capacitor of theinternal circuit(s) of the LED tube lamp for forming a capacitivevoltage divider network. Thereby, a division voltage applied in theinternal circuit(s) of the LED tube lamp is lower than the high voltageand high frequency AC driving signal, e.g.: the division voltage is in arange of 100-270V, and so no over voltage causes the internal circuit(s)damage. Alternatively, the switch terminals 1591 and 1592 is coupled tothe capacitor(s) of the terminal adapter circuit shown in FIG. 31A toFIG. 31C to have the signal flowing through the half-wave node as wellas the capacitor(s), e.g., the capacitor 642 in FIG. 31A, or thecapacitor 842 in FIG. 31C. When the high voltage and high frequency ACsignal generated by the lamp driving circuit 505 is input, the switchcircuit is cut off and so the capacitive voltage divider is performed;and when the low frequency AC signal of the commercial power or thedirect current of battery is input, the switch circuit bypasses thecapacitor(s).

It is worth noting that the switch circuit may have plural switch unitto have two or more switch terminal for being connected in parallel withplural capacitors, (e.g., the capacitors 645 and 645 in FIG. 31A, thecapacitors 643, 645 and 646 in FIG. 31A, the capacitors 743 and 744or/and the capacitors 745 and 746 in FIG. 30B, the capacitors 843 and844 in FIG. 31C, the capacitors 845 and 846 in FIG. 31C, the capacitors842, 843 and 844 in FIG. 31C, the capacitors 842, 845 and 846 in FIG.31C, and the capacitors 842, 843, 844, 845 and 846 in FIG. 31C) forbypassing the plural capacitor.

In addition, the ballast detection circuit can be used in conjunctionwith the mode switching circuits shown in FIG. 37A-37I. The switchcircuit of the ballast detection circuit is replaced with the modeswitching circuit. The detection circuit of the ballast detectioncircuit is coupled to one of the pins 501, 502, 503 and 504 fordetecting the signal input into the LED lamp through the pins 501, 502,503 and 504. The detection circuit generates a control signal to controlthe mode switching circuit being at the first mode or the second modeaccording to whether the signal is a high frequency, low frequency or DCsignal, i.e., the frequency of the signal.

For example, when the signal is a high frequency signal and higher thana defined mode switch frequency, such as the signal provided by the lampdriving circuit 505, the control signal generated by the detectioncircuit makes the mode switching circuit be at the second mode fordirectly inputting the filtered signal into the LED module. When thesignal is a low frequency signal or a direct signal and lower than thedefined mode switch frequency, such as the signal provided by thecommercial power or the battery, the control signal generated by thedetection circuit makes the mode switching circuit be at the first modefor directly inputting the filtered signal into the driving circuit.

Referring to FIG. 43A, a block diagram of an LED tube lamp in accordancewith a preferred embodiment is illustrated. Compared to that shown inFIG. 29D, the present embodiment comprises two rectifying circuits 510and 540, a filtering circuit 520, an LED lighting module 530, andfurther comprises an installation detection module 2520. Theinstallation detection module 2520 is coupled to the rectifying circuit510 (and/or the rectifying circuit 540) via an installation detectionterminal 2521 and is coupled to the filtering circuit 520 via aninstallation detection terminal 2522. The installation detection module2520 detects the signal through the installation detection terminals2521 and 2522 and determines whether cutting off an external drivingsignal passing through the LED tube lamp based on the detected result.When an LED tube lamp is not installed on a lamp socket or holder yet,the installation detection module 2520 detects a smaller current anddetermines the signal passing through a high impedance, and then it isin a cut-off state to make the LED tube lamp stop working. Otherwise,the installation detection module 2520 determines that the LED tube lamphas already been installed on the lamp socket or holder, and it keeps onconducting to make the LED tube lamp working normally. That is, when acurrent passing through the installation detection terminals is biggerthan or equal to a defined installation current (or a current value),the installation detection module is conductive to make the LED tubelamp operating in a conductive state based on determining that the LEDtube lamp has correctly been installed on the lamp socket or holder.When the current passing through the installation detection terminals issmaller than the defined installation current (or the current value),the installation detection module cuts off to make the LED tube lampentering in a non-conducting state based on determining that the LEDtube lamp has been not installed on the lamp socket or holder. Forexample, the installation detection module 2520 determines conducting orcutting off based on the impedance detection to make the LED tube lampoperating in conducting or entering non-conducting state. Accordingly,the problem of electric shock caused by touching the conductive part ofthe LED tube lamp which is incorrectly installed on the lamp socket orholder can be avoided.

Referring to FIG. 43B, a block diagram of an installation detectionmodule in accordance with an exemplary embodiment is illustrated. Theinstallation detection module includes a switch circuit 2580, adetection pulse generating module 2540, a detection result latchingcircuit 2560, and a detection determining circuit 2570. The detectiondetermining circuit 2570 is coupled to and detects the signal betweenthe installation detection terminals 2521 (through a switch circuitcoupling terminal 2581 and the switch circuit 2580) and 2522. It is alsocoupled to the detection result latching circuit 2560 via a detectionresult terminal 2571 to transmit the detection result signal. Thedetection pulse generating module 2540 is coupled to the detectionresult latching circuit 2560 via a pulse signal output terminal 2541,and generates a pulse signal to inform the detection result latchingcircuit 2560 of a time point for latching (storing) the detectionresult. The detection result latching circuit 2560 stores the detectionresult according to the detection result signal (or detection resultsignal and pulse signal), and transmits or responds the detection resultto the switch circuit 2580 coupled to the detection result latchingcircuit 2560 via a detection result latching terminal 2561. The switchcircuit 2580 controls the state in conducting or cutting off between theinstallation detection terminals 2521 and 2522 according to thedetection result.

Referring to FIG. 43C, a block diagram of a detection pulse generatingmodule in accordance with an exemplary embodiment is illustrated. Adetection pulse generating module 2640 includes multiple capacitors2642, 2645, and 2646, multiple resistors 2643, 2647, and 2648, twobuffers 2644, and 2651, an inverter 2650, a diode 2649, and an OR gate2652. With use or operation, the capacitor 2642 and the resistor 2643connect in serial between a driving voltage, such as VCC usually definedas a high logic level voltage, and a reference voltage (or potential),such as ground potential in this embodiment. The connection node of thecapacitor 2642 and the resistor 2643 is coupled to an input terminal ofthe buffer 2644. The resistor 2647 is coupled between the drivingvoltage, so-called VCC, and an input terminal of the inverter 2650. Theresistor 2648 is coupled between an input terminal of the buffer 2651and the reference voltage, e.g. ground potential in this embodiment. Ananode of the diode 2649 is grounded and a cathode thereof is coupled tothe input terminal of the buffer 2651. One ends of the capacitors 2645and 2646 are jointly coupled to an output terminal of the buffer 2644,the other ends of the capacitors 2645 and 2646 are respectively coupledto the input terminal of the inverter 2650 and the input terminal of thebuffer 2651. An output terminal of the inverter 2650 and an outputterminal of the buffer 2651 are coupled to two input terminals of the ORgate 2652. It's noteworthy that the voltage (or potential) for “highlogic level” and “low logic level” mentioned in this specification areall relative to another voltage (or potential) or a certain referredvoltage (or potential) in circuits, and further the voltage (orpotential) for “logic high logic level” and “logic low logic level.”

When an end cap of an LED tube lamp inserts a lamp socket and the otherend cap thereof is electrically coupled to human body or both end capsof the LED tube lamp insert the lamp socket, the LED tube lamp isconductive with electricity. At this moment, the installation detectionmodule enters a detection stage. The voltage on the connection node ofthe capacitor 2642 and the resistor 2643 is high initially (equals tothe driving voltage, VCC) and decreases with time to zero finally. Theinput terminal of the buffer 2644 is coupled to the connection node ofthe capacitor 2642 and the resistor 2643, so the buffer 2644 outputs ahigh logic level signal at the beginning and changes to output a lowlogic level signal when the voltage on the connection node of thecapacitor 2642 and the resistor 2643 decreases to a low logic triggerlogic level. That means, the buffer 2644 produces an input pulse signaland then keeps in low logic level thereafter (stops outputting the inputpulse signal). The pulse-width for the input pulse signal is equal toone (initial setting) specific duration keeping the signal level of theinput pulse signal on a logic high level, which is decided by thecapacitance value of the capacitor 2642 and the resistance value of theresistor 2643.

Next, the operations for the buffer 2644 to produce the pulse signalwith setting the time interval will be described below. Since thevoltage on the one ends of the capacitor 2645 and the resistor 2647 isequal to the driving voltage VCC, the voltage on the connection node ofthe capacitor 2645 and the resistor 2647 is also at a high logic level.The one end of the resistor 2648 is grounded and the one end of thecapacitor 2646 receives the pulse signal from the buffer 2644, so theconnection node of the capacitor 2646 and the resistor 2648 has a highlogic level voltage at the beginning but this voltage decreases withtime to zero (in the meanwhile, the capacitor stores the voltage beingequal to or approaching the driving voltage VCC.) Accordingly, theinverter 2650 outputs a low logic level signal and the buffer 2651outputs a high logic level signal, and hence the OR gate 2652 outputs ahigh logic level signal (a first pulse signal) at the pulse signaloutput terminal 2541. At this moment, the detection result latchingcircuit 2560 stores the detection result for the first time according tothe detection result signal and the pulse signal. When the voltage onthe connection node of the capacitor 2646 and the resistor 2648decreases to the low logic trigger logic level, the buffer 2651 changesto output a low logic level signal to make the OR gate 2652 output a lowlogic level signal at the pulse signal output terminal 2541 (stopsoutputting the first pulse signal.) The width of the first pulse signaloutput from the OR gate 2652 is determined by the capacitance value ofthe capacitor 2646 and the resistance value of the resistor 2648.

The operation after the buffer 2644 stopping outputting the pulse signalis described as below. That is, the operation is in an operating stage.Since the capacitor 2646 stores the voltage being almost equal to thedriving voltage VCC, and when the buffer 2644 instantaneously changesits output from a high logic level signal to a low logic level signal,the voltage on the connection node of the capacitor 2646 and theresistor 2648 is below zero but will be pulled up to zero by the diode2649 rapidly charging the capacitor. Therefore, the buffer 2651 stilloutputs a low logic level signal.

On the other hand, when the buffer 2644 instantaneously changes itsoutput from a high logic level signal to a low logic level signal, thevoltage on the one end of the capacitor 2645 also changes from thedriving voltage VCC to zero instantly. This makes the connection node ofthe capacitor 2645 and the resistor 2647 have a low logic level signal.At this moment, the output of the inverter 2650 changes to a high logiclevel signal to make the OR gate output a high logic level signal (asecond pulse signal.) The detection result latching circuit 2560 storesthe detection result for second time according to the detection resultsignal and the pulse signal. Next, the driving voltage VCC charges thecapacitor 2645 through the resistor 2647 to make the voltage on theconnection node of the capacitor 2645 and the resistor 2647 increaseswith the time to the driving voltage VCC. When the voltage on theconnection node of the capacitor 2645 and the resistor 2647 increases toreach a high logic trigger logic level, the inverter 2650 outputs a lowlogic level signal again to make the OR gate 2652 stop outputting thesecond pulse signal. The width of the second pulse signal is determinedby the capacitance value of the capacitor 2645 and the resistance valueof the resistor 2647.

As those mentioned above, the detection pulse generating module 2640generates two high logic level pulse signals in the detection stage,which are the first pulse signal and the second pulse signal and areoutput from the pulse signal output terminal 2541. Moreover, there is aninterval with a defined time between the first and second pulse signals,and the defined time is decided by the capacitance value of thecapacitor 2642 and the resistance value of the resistor 2643.

From the detection stage entering the operating stage, the detectionpulse generating module 2640 does not produce the pulse signal any more,and keeps the pulse signal output terminal 2541 on a low logic levelpotential. Referring to FIG. 43D, a detection determining circuit inaccordance with an exemplary embodiment is illustrated. A detectiondetermining circuit 2670 includes a comparator 2671, and a resistor2672. A negative input terminal of the comparator 2671 receives areference logic level signal (or a reference voltage) Vref, a positiveinput terminal thereof is grounded through the resistor 2672 and is alsocoupled to a switch circuit coupling terminal 2581. Referring to FIGS.43A and 43D, the signal flowing into the switch circuit 2580 from theinstallation detection terminal 2521 outputs to the switch circuitcoupling terminal 2581 via the resistor 2672. When the current of thesignal passing through the resistor 2672 is too big (that is, biggerthan or equal to a defined current for installation, e.g. 2A) and thismakes the voltage on the resistor 2672 bigger than the reference voltageVref (referring to two end caps inserting into the lamp socket,) thecomparator 2671 produces a high logic level detection result signal andoutputs it to the detection result terminal 2571. For example, when anLED tube lamp is correctly installed on a lamp socket, the comparator2671 outputs a high logic level detection result signal at the detectionresult terminal 2571, whereas the comparator 2671 generates a low logiclevel detection result signal and outputs it to the detection resultterminal 2571 when a current passing through the resistor 2672 isinsufficient to make the voltage on the resistor 2672 higher than thereference voltage Vref (referring to only one end cap inserting the lampsocket.) For example, when the LED tube lamp is incorrectly installed onthe lamp socket or one end cap thereof is inserted into the lamp socketbut the other one is grounded by a human body, the current will be toosmall to make the comparator 2671 output a low logic level detectionresult signal to the detection result terminal 2571.

Referring to FIG. 43E, a schematic detection result latching circuitaccording to some embodiments is illustrated. A detection resultlatching circuit 2660 includes a D flip-flop 2661, a resistor 2662, andan OR gate 2663. The D flip-flop 2661 has a CLK input terminal coupledto a detection result terminal 2571, and a D input terminal coupled to adriving voltage VCC. When the detection result terminal 2571 outputs alow logic level detection result signal, the D flip-flop 2661 outputs alow logic level signal at a Q output terminal thereof, but the Dflip-flop 2661 outputs a high logic level signal at the Q outputterminal thereof when the detection result terminal 2571 outputs a highlogic level detection result signal. The resistor 2662 is coupledbetween the Q output terminal of the D flip-flop 2661 and a referencevoltage, such as ground potential. When the OR gate 2663 receives thefirst or second pulse signals from the pulse signal output terminal 2541or receives a high logic level signal from the Q output terminal of theD flip-flop 2661, the OR gate 2663 outputs a high logic level detectionresult latching signal at a detection result latching terminal 2561. Thedetection pulse generating module 2640 only in the detection stageoutputs the first and the second pulse signals to make the OR gate 2663output the high logic level detection result latching signal, and the Dflip-flop 2661 decides the detection result latching signal to be highlogic level or low logic level in the rest time, e.g. including theoperating stage after the detection stage. Accordingly, when thedetection result terminal 2571 has no a high logic level detectionresult signal, the D flip-flop 2661 keeps a low logic level signal atthe Q output terminal to make the detection result latching terminal2561 also keeping a low logic level detection result latching signal inthe operating stage. On the contrary, once the detection result terminal2571 having a high logic level detection result signal, the D flip-flop2661 stores it and outputs and keeps a high logic level signal at the Qoutput terminal. In this way, the detection result latching terminal2561 keeps a high logic level detection result latching signal in theoperating stage as well.

Referring to FIG. 43F, a schematic switch circuit according to someembodiments is illustrated. A switch circuit 2680 includes a transistor,such as a bipolar junction transistor (BJT) 2681, as being a powertransistor, which has the ability of dealing with high current/power andis suitable for the switch circuit. The BJT 2681 has a collector coupledto an installation detection terminal 2521, a base coupled to adetection result latching terminal 2561, and an emitter coupled to aswitch circuit coupling terminal 2581. When the detection pulsegenerating module 2640 produces the first and second pulse signals, theBJT 2681 is in a transient conduction state. This allows the detectiondetermining circuit 2670 to perform the detection for determining thedetection result latching signal to be high logic level or low logiclevel. When the detection result latching circuit 2660 outputs a highlogic level detection result latching signal at the detection resultlatching terminal 2561, the BJT 2681 is in the conducting state to makethe installation detection terminals 2521 and 2522 conducting. Incontrast, when the detection result latching circuit 2660 outputs a lowlogic level detection result latching signal at the detection resultlatching terminal 2561, the BJT 2681 is cutting-off or in the blockingstate to make the installation detection terminals 2521 and 2522cutting-off or blocking.

The external driving signal is an AC signal. To avoid the detectionerror resulted from the logic level of the external driving signal beingjust around zero when the detection determining circuit 2670 detects,the detection pulse generating module 2640 generates the first andsecond pulse signals to let the detection determining circuit 2670performing twice detections. Consequently, the problem of the logiclevel of the external driving signal being just around zero in singledetection can be avoided. In some embodiments, the time differencebetween the productions of the first and second pulse signals is notmultiple times of half one cycle of the external driving signal. Forexample, it does not correspond to the multiple phase differences in 180degrees of the external driving signal. In this way, when one of thefirst and second pulse signals is generated and unfortunately theexternal driving signal is around zero, it can be avoided that theexternal driving signal is also around zero as another being generated.

The time difference between the productions of the first and secondpulse signals, for example, an interval with a defined time between themcan be represented as following:

Interval=(X+Y)(T/2),

where T represents the cycle of external driving signal, X is a naturalnumber, 0<Y<1, and Y is in the range of 0.05-0.95. In some embodiments,Y may be in the range of from 0.15 to 0.85.

To prevent the installation detection module from entering the detectionstage from misjudgment resulting from the logic level of the drivingvoltage VCC being too small, the first pulse signal can be set to beproduced when the driving voltage VCC reaches or is higher than adefined logic level. For example, in certain embodiments, the detectiondetermining circuit 2670 works after the driving voltage VCC reaches athreshold logic level to prevent the installation detection module frommalfunctioning due to an insufficient logic level.

According to certain embodiments mentioned above, when one end cap of anLED tube lamp is inserted into a lamp socket and the other one floats orelectrically couples to a human body, the detection determining circuitoutputs a low logic level detection result signal because of highimpedance. The detection result latching circuit stores the low logiclevel detection result signal based on the pulse signal of the detectionpulse generating module, making it as the low logic level detectionresult latching signal, and keeps the detection result in the operatingstage. In this way, the switch circuit keeps cutting-off or blockinginstead of conducting continually. And further, the electric shocksituation can be prevented and the requirement of safety standard canalso be met. On the other hand, when two end caps of the LED tube lampare correctly inserted into the lamp socket, the detection determiningcircuit outputs a high logic level detection result signal because theimpedance of the circuit for the LED tube lamp itself is small. Thedetection result latching circuit stores the high logic level detectionresult signal based on the pulse signal of the detection pulsegenerating module, making it as the high logic level detection resultlatching signal, and keeps the detection result in the operating stage.Thus, the switch circuit keeps conducting to make the LED tube lamp worknormally in the operating stage.

In some embodiments, when one end cap of the LED tube lamp is insertedinto the lamp socket and the other one floats or electrically couples toa human body, the detection determining circuit outputs a low logiclevel detection result signal to the detection result latching circuit,and then the detection pulse generating module outputs a low logic levelsignal to the detection result latching circuit to make the detectionresult latching circuit output a low logic level detection resultlatching signal to make the switch circuit cutting-off or blocking.Wherein, the switch circuit blocking makes the installation detectionterminals, e.g. the first and second installation detection terminals,blocking. That is, the LED tube lame is in non-conducting or blockingstate.

However, in some embodiments, when two end caps of the LED tube lamp arecorrectly inserted into the lamp socket, the detection determiningcircuit outputs a high logic level detection result signal to thedetection result latching circuit to make the detection result latchingcircuit output a high logic level detection result latching signal tomake the switch circuit conducting. Wherein, the switch circuitconducting makes the installation detection terminals, e.g. the firstand second installation detection terminals, conducting. That is, theLED tube lame operates in conducting state.

It is worth noting that in certain embodiments, the width of the pulsesignal generated by the detection pulse generating module is between 10μs to 1 ms, and it is used to make the switch circuit conducting for ashort period when the LED tube lamp conducts instantaneously. In thiscase, a pulse current is generated to pass through the detectiondetermining circuit for detecting and determining. Since the pulse isfor a short time and not for a long time, the electric shock situationwill not occur. Furthermore, the detection result latching circuit alsokeeps the detection result in the operating stage, and is no longerchanging the detection result stored previously complying with thecircuit state changing. The problem resulting from changing thedetection result may be avoided. The installation detection module, suchas the switch circuit, the detection pulse generating module, thedetection result latching circuit, and the detection determiningcircuit, could be integrated into a chip and then embedded in circuitsfor saving the circuit cost and layout space.

The LED tube lamps according to various different embodiments aredescribed as above. With respect to an entire LED tube lamp, thefeatures mentioned herein and in the embodiment may be applied inpractice singly or integrally such that one or more of the mentionedfeatures is practiced or simultaneously practiced.

According to certain embodiments of the power supply module, theexternal driving signal may be low frequency AC signal (e.g., commercialpower), high frequency AC signal (e.g., that provided by a ballast), ora DC signal (e.g., that provided by a battery), input into the LED tubelamp through a drive architecture of single-end power supply or dual-endpower supply. For the drive architecture of dual-end power supply, theexternal driving signal may be input by using only one end thereof assingle-end power supply.

The LED tube lamp may omit the rectifying circuit when the externaldriving signal is a DC signal.

According to certain embodiments of the rectifying circuit in the powersupply module, there may be a signal rectifying circuit, or dualrectifying circuit. First and second rectifying circuits of the dualrectifying circuit are respectively coupled to the two end caps disposedon two ends of the LED tube lamp. The single rectifying circuit isapplicable to the drive architecture of signal-end power supply, and thedual rectifying circuit is applicable to the drive architecture ofdual-end power supply. Furthermore, the LED tube lamp having at leastone rectifying circuit is applicable to the drive architecture of lowfrequency AC signal, high frequency AC signal or DC signal.

The single rectifying circuit may be a half-wave rectifier circuit orfull-wave bridge rectifying circuit. The dual rectifying circuit maycomprise two half-wave rectifier circuits, two full-wave bridgerectifying circuits or one half-wave rectifier circuit and one full-wavebridge rectifying circuit.

According to certain embodiments of the pin in the power supply module,there may be two pins in a single end (the other end has no pin), twopins in corresponding end of two ends, or four pins in corresponding endof two ends. The designs of two pins in single end two pins incorresponding end of two ends are applicable to signal rectifyingcircuit design of the of the rectifying circuit. The design of four pinsin corresponding end of two ends is applicable to dual rectifyingcircuit design of the of the rectifying circuit, and the externaldriving signal can be received by two pins in only one end or in twoends. And the pins may alternatively be called input terminals.

According to certain embodiments of the filtering circuit of the powersupply module, there may be a single capacitor, or n filter circuit. Thefiltering circuit filers the high frequency component of the rectifiedsignal for providing a DC signal with a low ripple voltage as thefiltered signal. The filtering circuit also further comprises the LCfiltering circuit having a high impedance for a specific frequency forconforming to current limitations in specific frequencies of the ULstandard. Moreover, the filtering circuit according to some embodimentsfurther comprises a filtering unit coupled between a rectifying circuitand the pin(s) for reducing the EMI.

According to certain embodiments of the LED lighting module in someembodiments, the LED lighting module may comprise the LED module and thedriving circuit, or only the LED module. The LED module is coupled to avoltage stabilization circuit for preventing the LED module fromovervoltage. The voltage stabilization circuit may be a voltage clampingcircuit, such as Zener diode, DIAC and so on. When the rectifyingcircuit has a capacitive circuit, in some embodiments, two capacitorsare respectively coupled between corresponding two pins in two end capsand so the two capacitors and the capacitive circuit as a voltagestabilization circuit perform a capacitive voltage divider.

If there are only the LED module in the LED lighting module and theexternal driving signal is a high frequency AC signal, a capacitivecircuit is in at least one rectifying circuit and the capacitive circuitis connected in series with a half-wave rectifier circuit or a full-wavebridge rectifying circuit of the rectifying circuit and serves as acurrent modulation circuit to modulate the current of the LED module dueto that the capacitor equates a resistor for a high frequency signal.Thereby, even different ballasts provide high frequency signals withdifferent voltage levels, the current of the LED module can be modulatedinto a defined current range for preventing overcurrent. In addition, anenergy-releasing circuit is connected in parallel with the LED module.When the external driving signal is no longer supplied, theenergy-releasing circuit releases the energy stored in the filteringcircuit to lower a resonance effect of the filtering circuit and othercircuits for restraining the flicker of the LED module.

In some embodiments, if there are the LED module and the driving circuitin the LED lighting module, the driving circuit may be a buck converter,a boost converter, or a buck-boost converter. The driving circuitstabilizes the current of the LED module at a defined current value, andthe defined current value may be modulated based on the external drivingsignal. For example, the defined current value may be increased with theincreasing of the level of the external driving signal and reduced withthe reducing of the level of the external driving signal. Moreover, amode switching circuit may be added between the LED module and thedriving circuit for switching the current from the filtering circuitdirectly or through the driving circuit inputting into the LED module.

A protection circuit may be additionally added to protect the LEDmodule. The protection circuit detects the current and/or the voltage ofthe LED module to determine whether to enable corresponding over currentand/or over voltage protection.

According to certain embodiments of the ballast detection circuit of thepower supply module, the ballast detection circuit is substantiallyconnected in parallel with a capacitor connected in series with the LEDmodule and determines the external driving signal whether flowingthrough the capacitor or the ballast detection circuit (i.e. bypassingthe capacitor) based on the frequency of the external driving signal.The capacitor may be a capacitive circuit in the rectifying circuit.

According to certain embodiments of the filament-simulating circuit ofthe power supply module, there is a single set of a parallel-connectedcapacitor and resistor, two serially connected sets, each having aparallel-connected capacitor and resistor, or a negative temperaturecoefficient circuit. The filament-simulating circuit is applicable toprogram-start ballast for avoiding the program-start ballast determiningthe filament abnormally, and so the compatibility of the LED tube lampwith program-start ballast is enhanced. Furthermore, thefilament-simulating circuit almost does not affect the compatibilitiesfor other ballasts, e.g., instant-start and rapid-start ballasts.

According to certain embodiments of the ballast-compatible circuit ofthe power supply module in some embodiments, the ballast-compatiblecircuit can be connected in series with the rectifying circuit orconnected in parallel with the filtering circuit and the LED lightingmodule. Under the design of being connected in series with therectifying circuit, the ballast-compatible circuit is initially in acutoff state and then changes to a conducting state in an objectivedelay. Under the design of being connected in parallel with thefiltering circuit and the LED lighting module, the ballast-compatiblecircuit is initially in a conducting state and then changes to a cutoffstate in an objective delay. The ballast-compatible circuit activateselectronic ballast during the starting stage and enhances thecompatibility for instant-start ballast. Furthermore, theballast-compatible circuit almost does not affect the compatibilitieswith other ballasts, e.g., program-start and rapid-start ballasts.

According to certain embodiments of the LED module of the power supplymodule, the LED module comprises a plurality of strings of LEDsconnected in parallel with each other, wherein each LED may have asingle LED chip or plural LED chips emitting different spectrums. EachLEDs in different LED strings is connected with each other to form amesh connection.

Having described at least one of the embodiments with reference to theaccompanying drawings, it will be apparent to those skills in the artthat the disclosure is not limited to those precise embodiments, andthat various modifications and variations can be made in the presentlydisclosed system without departing from the scope or spirit of thedisclosure. It is intended that the present disclosure covermodifications and variations of this disclosure provided they comewithin the scope of the appended claims and their equivalents.Specifically, one or more limitations recited throughout thespecification can be combined in any level of details to the extent theyare described to improve the LED tube lamp. These limitations include,but are not limited to: light transmissive portion and reinforcingportion; platform and bracing structure; vertical rib, horizontal riband curvilinear rib; thermally conductive plastic and light transmissiveplastic; silicone-based matrix having good thermal conductivity;anti-reflection layer; roughened surface; electrically conductive wiringlayer; wiring protection layer; ridge; maintaining stick; andshock-preventing safety switch.

While various aspects of the inventive concept have been described withreference to exemplary embodiments, it will be apparent to those skilledin the art that various changes and modifications may be made withoutdeparting from the spirit and scope of the inventive concept. Therefore,it should be understood that the disclosed embodiments are not limiting,but illustrative.

What is claimed is: 1-41. (canceled)
 42. An LED tube lamp, comprising: alamp tube; a reinforcing portion attached to an inner surface of thelamp tube, the reinforcing portion comprising a platform; an LED lightstrip disposed on the platform and thermally coupled to the reinforcingportion, the LED light strip comprising a wiring layer and a pluralityof LED light sources mounted on the wiring layer; a power supplydisposed on the reinforcing portion and configured to drive theplurality of LED light sources, the power supply comprising a circuitboard and a plurality of electronic components mounted on the circuitboard; and two end caps attached to two ends of the lamp tuberespectively, wherein, the plurality of electronic components areinterconnected to form a power supply module comprising at least arectifying circuit and a filtering circuit, the rectifying circuit iscoupled to two pins to receive an external signal, and the filteringcircuit is coupled to the rectifying circuit and is configured toreceive a signal from the rectifying circuit.
 43. The LED tube lamp ofclaim 42, wherein the LED light strip further comprises a protectionlayer disposed on a first surface of the wiring layer, the plurality ofLED light sources mounted on the first surface of the wiring layer. 44.The LED tube lamp of claim 43, wherein the LED light strip furthercomprises a dielectric layer disposed on a second surface of the wiringlayer.
 45. The LED tube lamp of claim 42, the reinforcing portionfurther comprising a curvilinear rib, wherein the curvilinear ribconnects to the platform and attaches to the inner surface of the lamptube.
 46. The LED tube lamp of claim 42, wherein the power supply modulefurther comprises an over voltage protection circuit, the over voltageprotection circuit coupled to the filtering circuit for detecting afiltered signal.
 47. The LED tube lamp of claim 42, wherein, the powersupply module further comprises a driving circuit, wherein the drivingcircuit is coupled to the filtering circuit and is configured to receivea signal from the filtering circuit.
 48. The LED tube lamp of claim 47,wherein the driving circuit comprises one of a buck converter, a boostconverter and a buck-boost converter.
 49. The LED tube lamp of claim 42,wherein the filtering circuit comprises a pi filter circuit comprisingtwo capacitors and one inductor.
 50. The LED tube lamp of claim 49,wherein the power supply module further comprises an installationdetection circuit, and the installation detection circuit is coupled tothe rectifying circuit and the filtering circuit.
 51. The LED tube lampof claim 50, wherein the power supply module further comprises a drivingcircuit, and the driving circuit is coupled to the filtering circuit andis configured to receive a signal from the filtering circuit.
 52. An LEDtube lamp, comprising: a lamp tube; a reinforcing portion comprising afirst surface and second surface, the reinforcing portion disposed inthe lamp tube by fixing the first surface on an inner surface of thelamp tube; an LED light strip disposed on the second surface of thereinforcing portion and thermally coupled to the reinforcing portion,the LED light strip comprising a wiring layer and a plurality of LEDlight sources mounted on the wiring layer; a power supply disposed onthe second surface of the reinforcing portion and configured to drivethe LED light source, the power supply comprising a circuit board and aplurality of electronic components mounted on the circuit board; and twoend caps attached to two ends of the lamp tube respectively, wherein,the plurality of electronic components are interconnected to form apower supply module comprising at least a rectifying circuit and afiltering circuit, the rectifying circuit is coupled to two pins toreceive an external signal, and the filtering circuit is coupled to therectifying circuit and is configured to receive a signal from therectifying circuit.
 53. The LED tube lamp of claim 52, wherein the LEDlight strip further comprises a protection layer disposed on a firstsurface of the wiring layer, the plurality of LED light sources mountedon the first surface of the wiring layer.
 54. The LED tube lamp of claim53, wherein the LED light strip further comprises a dielectric layerdisposed on a second surface of the wiring layer.
 55. The LED tube lampof claim 52, the reinforcing portion further comprising a curvilinearrib, wherein the curvilinear rib connects to a platform and attaches tothe inner surface of the lamp tube.
 56. The LED tube lamp of claim 52,wherein the power supply module further comprises an over voltageprotection circuit, the over voltage protection circuit coupled to thefiltering circuit for detecting a filtered signal.
 57. The LED tube lampof claim 52, wherein, the power supply module further comprises adriving circuit, and the driving circuit is coupled to the filteringcircuit and is configured to receive a signal from the filteringcircuit.
 58. The LED tube lamp of claim 57, wherein the driving circuitcomprises one of a buck converter, a boost converter and a buck-boostconverter.
 59. The LED tube lamp of claim 52, wherein the filteringcircuit comprises a pi filter circuit comprising two capacitors and oneinductor.
 60. The LED tube lamp of claim 59, wherein the power supplymodule further comprises an installation detection circuit, and theinstallation detection circuit is coupled to the rectifying circuit andthe filtering circuit.
 61. The LED tube lamp of claim 60, wherein thepower supply module further comprises a driving circuit, and the drivingcircuit is coupled to the filtering circuit and is configured to receivea signal from the filtering circuit.
 62. An LED tube lamp, comprising: alamp tube; a reinforcing portion comprising a first surface and secondsurface, the reinforcing portion disposed in the lamp tube by fixing thefirst surface on an inner surface of the lamp tube; an LED light stripdisposed on the second surface of the reinforcing portion and thermallycoupled to the reinforcing portion, the LED light strip comprising awiring layer and a plurality of LED light sources mounted on the wiringlayer; a power supply comprising a plurality of electronic componentsmounted on at least one end of the LED light strip and configured todrive the LED light source; and two end caps attached to two ends of thelamp tube respectively, wherein, the plurality of electronic componentsare interconnected to form a power supply module comprising at least arectifying circuit and a filtering circuit, the rectifying circuit iscoupled to two pins to receive an external signal, and the filteringcircuit is coupled to the rectifying circuit and is configured toreceive a signal from the rectifying circuit.
 63. The LED tube lamp ofclaim 62, wherein the LED light strip further comprises a protectionlayer disposed on a first surface of the wiring layer, the plurality ofLED light sources mounted on the first surface of the wiring layer. 64.The LED tube lamp of claim 63, wherein the LED light strip furthercomprises a dielectric layer disposed on a second surface of the wiringlayer.
 65. The LED tube lamp of claim 62, the reinforcing portionfurther comprising a curvilinear rib, wherein the curvilinear ribconnects to a platform and attaches to the inner surface of the lamptube.
 66. The LED tube lamp of claim 62, wherein the power supply modulefurther comprises an over voltage protection circuit, the over voltageprotection circuit coupled to the filtering circuit for detecting afiltered signal.
 67. The LED tube lamp of claim 62, wherein, the powersupply module further comprises a driving circuit, and the drivingcircuit is coupled to the filtering circuit and is configured to receivea signal from the filtering circuit.
 68. The LED tube lamp of claim 67,wherein the driving circuit comprises one of a buck converter, a boostconverter and a buck-boost converter.
 69. The LED tube lamp of claim 62,wherein the filtering circuit comprises a pi filter circuit comprisingtwo capacitors and one inductor.
 70. The LED tube lamp of claim 69,wherein the power supply module further comprises an installationdetection circuit, and the installation detection circuit is coupled tothe rectifying circuit and the filtering circuit.
 71. The LED tube lampof claim 70, wherein the plurality of electronic components areinterconnected further to form a driving circuit, and the drivingcircuit is coupled to the filtering circuit and is configured to receivea signal from the filtering circuit.
 72. The LED tube lamp of claim 1,wherein a portion of the reinforcing portion, a portion of the LED lightstrip, and a portion of the circuit board are stacked sequentially. 73.The LED tube lamp of claim 12, wherein a portion of the reinforcingportion, a portion of the LED light strip, and a portion of the circuitboard are stacked sequentially.